Syria fight rages amid pressure for talks Syrian rebels have kept up their resistance to a massive assault on the strategic central town of Qusayr as the regime's agreement to attend a planned peace conference boosted pressure on opposition leaders to match the move. The main opposition National Coalition has met in Istanbul for three days trying to overcome deep divisions over Russian and US proposals to convene a conference to which representatives of President Bashar al-Assad would be invited without any formal precondition for him to step down. It has been the opposition's long-standing position that after more than two years of devastating conflict that have killed more than 94,000 people it will not negotiate until Assad agrees to leave. The intervention of hundreds of fighters of Shi'ite militant group Hezbollah from neighbouring Lebanon has given the regime the upper hand in Qusayr. But almost a week after the regime assault began, fierce resistance continued from the rebels, for whom Qusayr provides an important supply line for arms and volunteers from neighbouring Lebanon. "The fighting and shelling, which took place on Saturday on the main roads inside and outside of Qusayr, are the most intense since the beginning of the offensive," said Syrian Observatory for Human Rights director Rami Abdul Rahman. "The town of Qusayr, and the rebel areas north of the town like Hamdiyeh, the former military airport at Dabaa and Arjuneh have been subjected to heavy bombardment by regime forces who are using surface-to-surface missiles," he said. Qusayr is a key prize for Assad's forces because of its strategic location between Damascus and the Mediterranean coast, the Alawite heartland of the embattled president's regime. Abdul Rahman said "the intensification of the fighting can be explained by Hezbollah's desire to score points before the speech their leader Hassan Nasrallah is due to deliver this evening." Saturday marked the 13th anniversary of Israel's withdrawal from south Lebanon after 22 years of occupation, and Nasrallah was due to address supporters to celebrate the occasion. His comments were being closely watched following rare criticism of Hezbollah on Friday from Lebanese President Michel Sleiman, who warned it against its intervention in Syria urging it to confine its activities to defence against Israel. Anti-regime demonstrators across Syria denounced the Hezbollah chief on Friday, waving placards reading "Nasrallah, impostor of the resistance," and "Homs is not Jerusalem," a reference to the Syrian central province in which Qusayr lies. To the concern of the international community, the offensive in Qusayr has sparked renewed clashes between Assad supporters and opponents inside Lebanon. Fighting between the rival sides in the Lebanese port of Tripoli has killed 28 people since Sunday, a security source said. In Istanbul, the opposition National Coalition, wrong-footed by Moscow's announcement that regime representatives had agreed to attend next month's planned peace conference, called on Damascus to give concrete evidence of its readiness for a transition of power. "It's very important for us to have goodwill gestures, and from both sides," National Coalition spokesman Khaled al-Saleh told reporters after a second day of talks on Friday. "We want to make sure that when we enter those negotiations the bloodshed in Syria will stop," he added. In terms of us making goodwill gestures, we're ready to make those. The US and Russia, which support opposite sides in Syria's raging conflict, announced their joint proposal for a Syria peace conference earlier this month. US Secretary of State John Kerry and Russian counterpart Sergei Lavrov are to meet in Paris on Monday to step up efforts to organise the conference.