Islamic State militants infiltrated a Palestinian refugee camp in Damascus today, marking the terrorist group's deepest foray the Syrian capital and seat of President Bashar Assad's power. ISIS entered the Yarmouk camp as Jordan closed its only functioning border crossing with the country following heavy clashes on the Syrian side between rebels and government forces. The militants, who already control large swaths of territory in northern Syria, reportedly entered the camp from the nearby Hajar Aswad neighborhood in southern Damascus in a coordinated attack with their rivals in the Al Qaeda-affiliated Nusra Front. According to the the UK-based Syrian Observatory for Human Rights, ISIS managed to take control of large parts of the Yarmouk camp following clashes with a Palestinian group. Jihadis: ISIS militants (pictured) entered the Yarmouk camp as Jordan closed its only functioning border crossing with the country following heavy clashes on the Syrian side between rebels and government forces . If ISIS manage to gain full control of Yarmouk, the jihadis can potentially use the camp as a base from which to threaten the heart of the capital as possibly challenge Assad himself. The Palestinian-run refugee camp  has been under government siege for nearly two years. U.N. aid workers have been sending food parcels into the camp, where thousands of civilians remain trapped and in desperate need of food and medicine. The camp had witnessed fighting in the past between government forces and militants who control much of the camp. The Observatory reported heavy clashes in the camp between IS fighters and members of the Palestinian faction called Aknaf Beit al-Maqdis. Residents of the Palestinian-run Yarmouk camp are seen queuing to receive food supplies last year . Anwar Raja, the spokesman for the pro-Assad Popular Front for the Liberation of Palestine said ISIS fighters entered the camp from nearby Hajar Aswad where they have been based for months. He added that today's push came was coordinated between ISIS and their rivals in the Nusra Front, Al Qaeda's branch in Syria. 'The Nusra Front opened the road for them in order to infiltrate the camp and several hours ago they entered Yarmouk,' Raja said by telephone. It was not immediately clear why Nusra - who have repeatedly fought against ISIS over the past year - would facilitate the entry of the group into the camp. A Syrian foreign ministry statement today said it holds Jordan responsible for 'obstructing the movement of trucks and passengers and any ensuing economic or social repercussions.' U.N relief workers with blue helmets and vests stand next of residents of the Yarmouk camp one year ago . Jordanian government spokesman Mohammed al-Momani said that the Nasib crossing was temporarily closed late last night because of clashes nearby. 'It is important for us to keep the safety for the passengers and those who are trying to cross between the two countries,' he said. 'So we decided to close the border temporarily, until things calm down. Then we will open it again.' A spokesman for rebels in southern Syria, Issam al-Rayess, confirmed that rebel fighters were trying to take control of the border crossing from Syrian authorities. The Nasib crossing is the only functioning crossing between Jordan and Syria and is considered a crucial gateway for Syria's government and for Syrian, Lebanese and Jordanian traders and merchants. Gruesome new images have emerged showing Islamic State militants stoning a blindfolded and bound man and woman to death in Iraq after they were accused of having sex before marriage. Taken in the ISIS-stronghold of Mosul in Nineveh province, the shocking images show a large crowd gathered to watch the jihadis murder the defenceless couple. Young boys clamber onto their fathers' shoulders to get a better view of the man and woman being charged with 'fornication', before the familiar white-bearded face of ISIS's elderly Mosul-based executioner-in-chief Abu Ansar al-Ansari orders their stoning to death. The sickening images begin by showing a large crowd gathered in a rain-drenched square in central Mosul. Stoned to death: Taken in the ISIS-stronghold of Mosul in Nineveh province, the shocking images show a large crowd gathered to watch the ISIS militants murder the defenceless couple . Bloodthirsty: With heavily armed militants taking up positions on ledges overlooking the crowd, the young men and boys jostle to ensure they get the best view of the murder . With heavily armed militants taking up positions on ledges overlooking the crowd, the young men and boys jostle to ensure they get the best view of the murder . In the background of the image, women wearing black niqabs are seen gathered together. An Islamic State militant with a yellow scarf covering his face is then seen using a microphone and PA system to read out the charge of 'fornication' against the couple, suggesting they have been accused of having sex without being married, not of committing adultery. A large pile of stones are then seen heaped in the middle of the road, before the barbaric ISIS militants began throwing them at the defenceless and blindfolded couple, who have had their hands bound to prevent them getting away. As stones rain down on the victims' bodies, large pools of blood appear in the road, before eventually the man and woman die of their injuries and the savagery finally comes to an end. Preparing to kill: After the charges are read out, the familiar white-bearded face of ISIS' elderly Mosul-based executioner-in-chief Abu Ansar al-Ansari (centre) orders their stoning to death .
Jihadis entered the camp through the nearby Hajar Aswad neighborhood .
Al Qaeda-linked rebels reportedly opened a closed road for ISIS militants .
Once inside extremists battled a Palestinian group who run the camp .
Terrorists seized control of the majority of the refugee camp, which they are now likely to use as a base from which to Assad .