ANKARA/BEIRUT (Reuters) - Syrian rebels backed by the Turkish military have captured the outskirts of the Islamic State-held city of al-Bab in northern Syria, the Turkish government and rebel sources said on Wednesday.

The advance threatens an important Islamic State stronghold, whose fall would deepen Turkish influence in an area of northern Syria where it has created a de facto buffer zone.

Syrian government forces have also advanced on al-Bab from the south, bringing them close to their Turkish and rebel enemies in one of the most complex battlefields of the six-year-old conflict.

But Turkey said international coordination was under way to prevent clashes with the Syrian forces.

“The al-Bab operation must be completed immediately in the period ahead ... In recent days our special forces and the Free Syrian Army (rebels) have made serious progress,” Turkish Foreign Minister Mevlut Cavusoglu told a news conference.

In a sign of Turkish momentum and confidence, the government said its next target would be the Syrian city of Raqqa, de facto capital of the embattled Islamic State group which has also been partly dislodged from its Iraqi stronghold of Mosul.

The U.S. military, which is leading an international coalition against Islamic State, said it expected Raqqa to be “completely isolated” in the next few weeks.

COORDINATION WITH RUSSIA

Al-Bab has been a major target of a Turkish offensive launched in northern Syria last August to drive Islamic State away from the border and prevent further gains by U.S.-backed Kurdish militia that are also fighting the jihadist group. The city is just 30 km (20 miles) from the Turkish border.

A Free Syrian Army rebel commander speaking to Reuters from the southeastern outskirts of al-Bab said Syrian government planes and helicopters were visible to the west of his position, saying there was now an “indirect frontline” between the sides.

But an official in a military alliance backing Syrian President Bashar al-Assad said the city was being left to Turkish control, in what appeared to be part of a de facto deal with Russia, Assad’s most powerful ally.

Turkish Prime Minister Binali Yildirim said clashes with the Syrian forces had been avoided.

“As a result of coordination between coalition forces, the Turkish air force and Russia, necessary measures are being taken to prevent any unpleasant incidents or clashes,” Yildirim said.

Assad has been backed in the war by the Russian air force and an array of Iranian-backed Shi’ite militias. The Syrian army advance towards al-Bab is aimed at preventing deeper Turkish advances and safeguarding the city of Aleppo, 50 km (30 miles) to the southwest.

Syrian Democratic Forces (SDF) fighters gather during an offensive against Islamic State militants in northern Raqqa province, Syria February 8, 2017. REUTERS/Rodi Said

“PROGRESS IS FAST”

The Turkish military said in a statement that 58 Islamic State militants had been killed in air strikes, artillery fire and clashes. Four Turkish soldiers had been killed and at least a dozen wounded. The advancing forces had captured strategic hilltops around al-Bab, the army said.

A Syrian rebel fighter reached by Reuters said he was speaking from inside al-Bab where he said Islamic State lines were collapsing. “Praise God, the progress is fast,” he said.

The Syrian Observatory for Human Rights, a UK-based organization that reports on the war, cautioned that it was not yet clear if Islamic State had collapsed entirely in the city. It said at least six people had been killed and 12 more wounded in the latest shelling there.

The organization says Turkish bombardment has killed scores of people since December. Turkey says it has been careful to avoid civilian casualties.

Islamic State is being fought by three separate military alliances in northern Syria, including the U.S.-backed Syrian Democratic Forces which incorporate the Kurdish YPG militia.

U.S. support for the YPG has angered Turkey, which views it as an extension of a Kurdish militia that is waging an insurgency in Turkey.

A spokesman for Turkish President Tayyip Erdogan said Turkey had presented a detailed plan to drive Islamic State out of Raqqa and discussions on the issue were under way.

Slideshow (11 Images)

Spokesman Ibrahim Kalin told broadcaster NTV there had been better coordination with the U.S.-led coalition on air strikes in the last 10 days and Ankara’s priority was to establish a safe zone between the Syrian towns of Azaz and Jarablus, which are just over the border.

The safe zone is an important goal for Ankara because it would mean that civilians displaced by the conflict could be provided for in Syria, rather than crossing into Turkey.

Turkish sources said Erdogan and U.S. President Donald Trump agreed in a phone call overnight to act jointly against Islamic State in al-Bab and Raqqa.

The White House said in a statement that Trump spoke about the two countries’ “shared commitment to combating terrorism in all its forms” and welcomed Turkey’s contributions to the fight against Islamic State, but it gave no further details.</s>Syrian rebels backed by the Turkish military have captured the outskirts of the Islamic State-held city of al-Bab in northern Syria, the Turkish government and rebel sources said on Wednesday.

The advance threatens an important Islamic State stronghold, whose fall would deepen Turkish influence in an area of northern Syria where it has created a de facto buffer zone.

Syrian government forces have also advanced on al-Bab from the south, bringing them close to their Turkish and rebel enemies in one of the most complex battlefields of the six-year-old conflict.

But Turkey said international coordination was under way to prevent clashes with the Syrian forces.

“The al-Bab operation must be completed immediately in the period ahead ... In recent days our special forces and the Free Syrian Army (rebels) have made serious progress,” Turkish Foreign Minister Mevlut Cavusoglu told a news conference.

In a sign of Turkish momentum and confidence, the government said its next target would be the Syrian city of Raqqa, de facto capital of the embattled Islamic State group which has also been partly dislodged from its Iraqi stronghold of Mosul.

The U.S. military, which is leading an international coalition against Islamic State, said it expected Raqqa to be

 “completely isolated” in the next few weeks.

Al-Bab has been a major target of a Turkish offensive launched in northern Syria last August to drive Islamic State away from the border and prevent further gains by U.S.-backed Kurdish militia that are also fighting the jihadist group. The city is just 30 km (20 miles) from the Turkish border.

A Free Syrian Army rebel commander speaking to Reuters from the southeastern outskirts of al-Bab said Syrian government planes and helicopters were visible to the west of his position, saying there was now an “indirect frontline” between the sides.

But an official in a military alliance backing Syrian President Bashar al-Assad said the city was being left to Turkish control, in what appeared to be part of a de facto deal with Russia, Assad’s most powerful ally.

Turkish Prime Minister Binali Yildirim said clashes with the Syrian forces had been avoided.

“As a result of coordination between coalition forces, the Turkish air force and Russia, necessary measures are being taken to prevent any unpleasant incidents or clashes,” Yildirim said.

Assad has been backed in the war by the Russian air force and an array of Iranian-backed Shi’ite militias. The Syrian army advance towards al-Bab is aimed at preventing deeper Turkish advances and safeguarding the city of Aleppo, 50 km (30 miles) to the southwest.

The Turkish military said in a statement that 58 Islamic State militants had been killed in air strikes, artillery fire and clashes. Four Turkish soldiers had been killed and at least a dozen wounded. The advancing forces had captured strategic hilltops around al-Bab, the army said.

A Syrian rebel fighter reached by Reuters said he was speaking from inside al-Bab where he said Islamic State lines were collapsing. “Praise God, the progress is fast,” he said.

The Syrian Observatory for Human Rights, a UK-based organisation that reports on the war, cautioned that it was not yet clear if Islamic State had collapsed entirely in the city. It said at least six people had been killed and 12 more wounded in the latest shelling there.

The organisation says Turkish bombardment has killed scores of people since December. Turkey says it has been careful to avoid civilian casualties.

Islamic State is being fought by three separate military alliances in northern Syria, including the U.S.-backed Syrian Democratic Forces which incorporate the Kurdish YPG militia.

U.S. support for the YPG has angered Turkey, which views it as an extension of a Kurdish militia that is waging an insurgency in Turkey.

A spokesman for Turkish President Tayyip Erdogan said Turkey had presented a detailed plan to drive Islamic State out of Raqqa and discussions on the issue were under way.

Spokesman Ibrahim Kalin told broadcaster NTV there had been better coordination with the U.S.-led coalition on air strikes in the last 10 days and Ankara’s priority was to establish a safe zone between the Syrian towns of Azaz and Jarablus, which are just over the border.

The safe zone is an important goal for Ankara because it would mean that civilians displaced by the conflict could be provided for in Syria, rather than crossing into Turkey.

Turkish sources said Erdogan and U.S. President Donald Trump agreed in a phone call overnight to act jointly against Islamic State in al-Bab and Raqqa.

The White House said in a statement that Trump spoke about the two countries’ “shared commitment to combating terrorism in all its forms” and welcomed Turkey’s contributions to the fight against Islamic State, but it gave no further details.</s>Syrian rebels supported by Turkish armed forces have seized control of strategically important hills around the Islamic State-controlled town of al-Bab, Turkey’s military said on Wednesday.

It said in a statement that 58 Islamic State militants were killed in air strikes, artillery fire and clashes. Two Turkish soldiers had been killed and 15 slightly wounded.

Turkish Foreign Minister Mevlut Cavusoglu said the operations had made important progress and the next target would be the Syrian city of Raqqa, the de facto capital of Islamic State.

“The al-Bab operation must be completed immediately in the period ahead … In recent days our special forces and the Free Syrian Army (rebels) have made serious progress,” Cavusoglu told a news conference in the capital Ankara.

The battle for al-Bab has raised the prospect of confrontation between the Turkish military and the Syrian army, which has pushed to within a few kilometres of the city’s southern outskirts.

A Syrian rebel official and a monitoring organisation said the advancing rebel and Turkish forces had captured the western outskirts of al-Bab, some 30 km (20 miles) south of the Turkish border.

“With last night’s assault, Islamic State’s defences have been broken through and the advance is now continuing,” said the official, speaking from the Turkish city of Gaziantep. Turkish military reinforcements had been sent to the area about a week ago, the rebel added.

Al-Bab has been a major target of a Turkish offensive launched in northern Syria last August to drive Islamic State away from the border and prevent further gains by US-backed Kurdish militia that are also fighting the jihadist group.

Syrian government forces and allied militia have mounted their own rapid advance towards al-Bab in the last few weeks. The city was encircled earlier this week when Syrian government forces cut the last way into the city.

The Syrian Observatory for Human Rights, a UK-based organisation that reports on the war, said the Turkish forces and their Free Syrian Army rebel allies had captured a hill on the western periphery of the city.

“We don’t know if Daesh (Islamic State) will be able to recover it, or if it is in a state of collapse,” Observatory Director Rami Abdulrahman said.

In a video sent by the rebel official, three Syrian rebel fighters with the Sultan Murad faction said they were speaking from inside al-Bab. It was not possible to confirm the authenticity of the footage.

“I am in Bab now but not at the centre. We are on the outskirts. Thank God, we have reached this place,” said one of the rebels. Blasts were heard in the background.

The Observatory said at least six people had been killed and 12 more wounded in the latest shelling of al-Bab.

The organisation says Turkish bombardment has killed scores of people since December. Turkey says it has been careful to avoid civilian casualties.

Turkish presidency sources said on Wednesday President Tayyip Erdogan and US President Donald Trump agreed in a phone call overnight to act jointly against Islamic State in al-Bab and Raqqa, another Syrian city held by IS.

The White House said in a statement that Trump spoke about the two countries’ “shared commitment to combating terrorism in all its forms” and welcomed Turkey’s contributions to the fight against Islamic State, but it gave no further details.</s>Turkish army and Syrian rebels close in on Islamic State town

ANKARA/BEIRUT, Feb 8 (Reuters) - Syrian rebels supported by Turkish armed forces have seized control of strategically important hills around the Islamic State-controlled town of al-Bab, Turkey's military said on Wednesday.

It said in a statement that 58 Islamic State militants were killed in air strikes, artillery fire and clashes. Two Turkish soldiers had been killed and 15 slightly wounded.

Turkish Foreign Minister Mevlut Cavusoglu said the operations had made important progress and the next target would be the Syrian city of Raqqa, the de facto capital of Islamic State.

"The al-Bab operation must be completed immediately in the period ahead ... In recent days our special forces and the Free Syrian Army (rebels) have made serious progress," Cavusoglu told a news conference in the capital Ankara.

The battle for al-Bab has raised the prospect of confrontation between the Turkish military and the Syrian army, which has pushed to within a few kilometres of the city's southern outskirts.

A Syrian rebel official and a monitoring organisation said the advancing rebel and Turkish forces had captured the western outskirts of al-Bab, some 30 km (20 miles) south of the Turkish border.

"With last night's assault, Islamic State's defences have been broken through and the advance is now continuing," said the official, speaking from the Turkish city of Gaziantep. Turkish military reinforcements had been sent to the area about a week ago, the rebel added.

Al-Bab has been a major target of a Turkish offensive launched in northern Syria last August to drive Islamic State away from the border and prevent further gains by U.S.-backed Kurdish militia that are also fighting the jihadist group.

Syrian government forces and allied militia have mounted their own rapid advance towards al-Bab in the last few weeks. The city was encircled earlier this week when Syrian government forces cut the last way into the city.

The Syrian Observatory for Human Rights, a UK-based organisation that reports on the war, said the Turkish forces and their Free Syrian Army rebel allies had captured a hill on the western periphery of the city.

"We don't know if Daesh (Islamic State) will be able to recover it, or if it is in a state of collapse," Observatory Director Rami Abdulrahman said.

In a video sent by the rebel official, three Syrian rebel fighters with the Sultan Murad faction said they were speaking from inside al-Bab. It was not possible to confirm the authenticity of the footage.

"I am in Bab now but not at the centre. We are on the outskirts. Thank God, we have reached this place," said one of the rebels. Blasts were heard in the background.

The Observatory said at least six people had been killed and 12 more wounded in the latest shelling of al-Bab.

The organisation says Turkish bombardment has killed scores of people since December. Turkey says it has been careful to avoid civilian casualties.

Turkish presidency sources said on Wednesday President Tayyip Erdogan and U.S. President Donald Trump agreed in a phone call overnight to act jointly against Islamic State in al-Bab and Raqqa, another Syrian city held by IS.

The White House said in a statement that Trump spoke about the two countries' "shared commitment to combating terrorism in all its forms" and welcomed Turkey's contributions to the fight against Islamic State, but it gave no further details. (Additional reporting by Nevzat Devranoglu, Gulsen Solaker, Ece Toksabay and Orhan Coskun; Editing by Mark Trevelyan)</s>ISTANBUL/BEIRUT: The Turkish army and allied Syrian rebels have captured the western outskirts of the Islamic State-held city of al-Bab, a rebel official and war monitor said on Wednesday, escalating their assault as the Syrian army also advanced on the city.

"With last night’s assault, Islamic State’s defences have been broken through and the advance is now continuing," said a Turkmen Syrian rebel official, speaking from the Turkish city of Gaziantep.

Syrian government forces have advanced to within a few kilometres (miles) of al-Bab, which is located 40 km (25 miles) northeast of Aleppo. The separate campaign by the Syrian army has raised the risk of a clash with the Turkish military.

The Syrian Observatory for Human Rights, a UK-based organisation that reports on the war, said the Turkish forces and their Free Syrian Army rebel allies had captured a hill on the western periphery of the city.

"We don't know if Daesh (Islamic State) will be able to recover it, or if it is in a state of collapse," Observatory Director Rami Abdulrahman said. The rebel official said Turkish reinforcements had been sent to the area a week ago.</s>ISTANBUL/BEIRUT (Reuters) - The Turkish army and allied Syrian rebels have captured the western outskirts of the Islamic State-held city of al-Bab, a rebel official and war monitor said on Wednesday, escalating their assault as the Syrian army also advanced on the city.

"With last night’s assault, Islamic State’s defenses have been broken through and the advance is now continuing," said a Turkmen Syrian rebel official, speaking from the Turkish city of Gaziantep.

Syrian government forces have advanced to within a few kilometers (miles) of al-Bab, which is located 40 km (25 miles) northeast of Aleppo. The separate campaign by the Syrian army has raised the risk of a clash with the Turkish military.

The Syrian Observatory for Human Rights, a UK-based organization that reports on the war, said the Turkish forces and their Free Syrian Army rebel allies had captured a hill on the western periphery of the city.

"We don't know if Daesh (Islamic State) will be able to recover it, or if it is in a state of collapse," Observatory Director Rami Abdulrahman said. The rebel official said Turkish reinforcements had been sent to the area a week ago.</s>ISTANBUL/BEIRUT: The Turkish army and allied Syrian rebels have captured the western outskirts of the Islamic State-held city of al-Bab, a rebel official and war monitor said on Wednesday, escalating their assault as the Syrian army also advanced on the city.

"With last night’s assault, Islamic State’s defences have been broken through and the advance is now continuing," said a Turkmen Syrian rebel official, speaking from the Turkish city of Gaziantep.

Syrian government forces have advanced to within a few kilometres (miles) of al-Bab, which is located 40 km (25 miles) northeast of Aleppo. The separate campaign by the Syrian army has raised the risk of a clash with the Turkish military.

The Syrian Observatory for Human Rights, a UK-based organisation that reports on the war, said the Turkish forces and their Free Syrian Army rebel allies had captured a hill on the western periphery of the city.

"We don't know if Daesh (Islamic State) will be able to recover it, or if it is in a state of collapse," Observatory Director Rami Abdulrahman said. The rebel official said Turkish reinforcements had been sent to the area a week ago.</s>The advance threatens an important Islamic State stronghold, whose fall would deepen Turkish influence in an area of northern Syria where it has created a de facto buffer zone.

Syrian government forces have also advanced on al-Bab from the south, bringing them close to their Turkish and rebel enemies in one of the most complex battlefields of the six-year-old conflict.

But Turkey said international coordination was under way to prevent clashes with the Syrian forces.

"The al-Bab operation must be completed immediately in the period ahead ... In recent days our special forces and the Free Syrian Army (rebels) have made serious progress," Turkish Foreign Minister Mevlut Cavusoglu told a news conference.

In a sign of Turkish momentum and confidence, the government said its next target would be the Syrian city of Raqqa, de facto capital of the embattled Islamic State group which has also been partly dislodged from its Iraqi stronghold of Mosul.

The U.S. military, which is leading an international coalition against Islamic State, said it expected Raqqa to be "completely isolated" in the next few weeks.

Al-Bab has been a major target of a Turkish offensive launched in northern Syria last August to drive Islamic State away from the border and prevent further gains by U.S.-backed Kurdish militia that are also fighting the jihadist group. The city is just 30 km (20 miles) from the Turkish border.

A Free Syrian Army rebel commander speaking to Reuters from the southeastern outskirts of al-Bab said Syrian government planes and helicopters were visible to the west of his position, saying there was now an "indirect frontline" between the sides.

But an official in a military alliance backing Syrian President Bashar al-Assad said the city was being left to Turkish control, in what appeared to be part of a de facto deal with Russia, Assad's most powerful ally.

Turkish Prime Minister Binali Yildirim said clashes with the Syrian forces had been avoided.

"As a result of coordination between coalition forces, the Turkish air force and Russia, necessary measures are being taken to prevent any unpleasant incidents or clashes," Yildirim said.

Assad has been backed in the war by the Russian air force and an array of Iranian-backed Shi'ite militias. The Syrian army advance towards al-Bab is aimed at preventing deeper Turkish advances and safeguarding the city of Aleppo, 50 km (30 miles) to the southwest.

The Turkish military said in a statement that 58 Islamic State militants had been killed in air strikes, artillery fire and clashes. Four Turkish soldiers had been killed and at least a dozen wounded. The advancing forces had captured strategic hilltops around al-Bab, the army said.

A Syrian rebel fighter reached by Reuters said he was speaking from inside al-Bab where he said Islamic State lines were collapsing. "Praise God, the progress is fast," he said.

The Syrian Observatory for Human Rights, a UK-based organization that reports on the war, cautioned that it was not yet clear if Islamic State had collapsed entirely in the city. It said at least six people had been killed and 12 more wounded in the latest shelling there.

The organization says Turkish bombardment has killed scores of people since December. Turkey says it has been careful to avoid civilian casualties.

Islamic State is being fought by three separate military alliances in northern Syria, including the U.S.-backed Syrian Democratic Forces which incorporate the Kurdish YPG militia.

U.S. support for the YPG has angered Turkey, which views it as an extension of a Kurdish militia that is waging an insurgency in Turkey.

A spokesman for Turkish President Tayyip Erdogan said Turkey had presented a detailed plan to drive Islamic State out of Raqqa and discussions on the issue were under way.

Spokesman Ibrahim Kalin told broadcaster NTV there had been better coordination with the U.S.-led coalition on air strikes in the last 10 days and Ankara's priority was to establish a safe zone between the Syrian towns of Azaz and Jarablus, which are just over the border.

The safe zone is an important goal for Ankara because it would mean that civilians displaced by the conflict could be provided for in Syria, rather than crossing into Turkey.

Turkish sources said Erdogan and U.S. President Donald Trump agreed in a phone call overnight to act jointly against Islamic State in al-Bab and Raqqa.

The White House said in a statement that Trump spoke about the two countries' "shared commitment to combating terrorism in all its forms" and welcomed Turkey's contributions to the fight against Islamic State, but it gave no further details.</s>ANKARA/BEIRUT: Syrian rebels supported by Turkish armed forces have seized control of strategically important hills around the Islamic State-controlled town of al-Bab, Turkey's military said on Wednesday.

It said in a statement that 58 Islamic State militants were killed in air strikes, artillery fire and clashes. Two Turkish soldiers had been killed and 15 slightly wounded.

Turkish Foreign Minister Mevlut Cavusoglu said the operations had made important progress and the next target would be the Syrian city of Raqqa, the de facto capital of Islamic State.

"The al-Bab operation must be completed immediately in the period ahead ... In recent days our special forces and the Free Syrian Army (rebels) have made serious progress," Cavusoglu told a news conference in the capital Ankara.

The battle for al-Bab has raised the prospect of confrontation between the Turkish military and the Syrian army, which has pushed to within a few kilometres of the city's southern outskirts.

A Syrian rebel official and a monitoring organisation said the advancing rebel and Turkish forces had captured the western outskirts of al-Bab, some 30 km (20 miles) south of the Turkish border.

"With last night’s assault, Islamic State’s defences have been broken through and the advance is now continuing," said the official, speaking from the Turkish city of Gaziantep. Turkish military reinforcements had been sent to the area about a week ago, the rebel added.

Al-Bab has been a major target of a Turkish offensive launched in northern Syria last August to drive Islamic State away from the border and prevent further gains by U.S.-backed Kurdish militia that are also fighting the jihadist group.

Syrian government forces and allied militia have mounted their own rapid advance towards al-Bab in the last few weeks. The city was encircled earlier this week when Syrian government forces cut the last way into the city.

The Syrian Observatory for Human Rights, a UK-based organisation that reports on the war, said the Turkish forces and their Free Syrian Army rebel allies had captured a hill on the western periphery of the city.

"We don't know if Daesh (Islamic State) will be able to recover it, or if it is in a state of collapse," Observatory Director Rami Abdulrahman said.

In a video sent by the rebel official, three Syrian rebel fighters with the Sultan Murad faction said they were speaking from inside al-Bab. It was not possible to confirm the authenticity of the footage.

"I am in Bab now but not at the centre. We are on the outskirts. Thank God, we have reached this place," said one of the rebels. Blasts were heard in the background.

The Observatory said at least six people had been killed and 12 more wounded in the latest shelling of al-Bab.

The organisation says Turkish bombardment has killed scores of people since December. Turkey says it has been careful to avoid civilian casualties.

Turkish presidency sources said on Wednesday President Tayyip Erdogan and U.S. President Donald Trump agreed in a phone call overnight to act jointly against Islamic State in al-Bab and Raqqa, another Syrian city held by IS.

The White House said in a statement that Trump spoke about the two countries' "shared commitment to combating terrorism in all its forms" and welcomed Turkey's contributions to the fight against Islamic State, but it gave no further details.</s>Ankara/Beirut: Syrian rebels supported by Turkish armed forces have seized control of strategically important hills around the Islamic State-controlled town of al-Bab, Turkey's military said on Wednesday.

It said in a statement that 58 Islamic State militants were killed in air strikes, artillery fire and clashes. Two Turkish soldiers had been killed and 15 slightly wounded.

Turkish Foreign Minister Mevlut Cavusoglu said the operations had made important progress and the next target would be the Syrian city of Raqqa, the de facto capital of Islamic State.

"The al-Bab operation must be completed immediately in the period ahead. In recent days our special forces and the Free Syrian Army (rebels) have made serious progress," Cavusoglu told a news conference in the capital Ankara.

The battle for al-Bab has raised the prospect of confrontation between the Turkish military and the Syrian army, which has pushed to within a few kilometres of the city's southern outskirts.

A Syrian rebel official and a monitoring organisation said the advancing rebel and Turkish forces had captured the western outskirts of al-Bab, some 30 km (20 miles) south of the Turkish border.

"With last night’s assault, Islamic State’s defences have been broken through and the advance is now continuing," said the official, speaking from the Turkish city of Gaziantep. Turkish military reinforcements had been sent to the area about a week ago, the rebel added.

Al-Bab has been a major target of a Turkish offensive launched in northern Syria last August to drive Islamic State away from the border and prevent further gains by U.S.-backed Kurdish militia that are also fighting the jihadist group.

Syrian government forces and allied militia have mounted their own rapid advance towards al-Bab in the last few weeks. The city was encircled earlier this week when Syrian government forces cut the last way into the city.

The Syrian Observatory for Human Rights, a UK-based organisation that reports on the war, said the Turkish forces and their Free Syrian Army rebel allies had captured a hill on the western periphery of the city.

"We don't know if Daesh (Islamic State) will be able to recover it, or if it is in a state of collapse," Observatory Director Rami Abdulrahman said.

In a video sent by the rebel official, three Syrian rebel fighters with the Sultan Murad faction said they were speaking from inside al-Bab. It was not possible to confirm the authenticity of the footage.

"I am in Bab now but not at the centre. We are on the outskirts. Thank God, we have reached this place," said one of the rebels. Blasts were heard in the background.

The Observatory said at least six people had been killed and 12 more wounded in the latest shelling of al-Bab.

The organisation says Turkish bombardment has killed scores of people since December. Turkey says it has been careful to avoid civilian casualties.

Turkish presidency sources said on Wednesday President Tayyip Erdogan and U.S. President Donald Trump agreed in a phone call overnight to act jointly against Islamic State in al-Bab and Raqqa, another Syrian city held by IS.

The White House said in a statement that Trump spoke about the two countries "shared commitment to combating terrorism in all its forms" and welcomed Turkey`s contributions to the fight against Islamic State, but it gave no further details.
Syrian rebels, with backing from the Turkish Armed Forces, advance on ISIL-held al-Bab, capturing the outskirts of the town.