ISTANBUL — Syria's fractious opposition scrambled to agree a new leadership Friday in a bid to present a coherent front at peace talks which the United States and Russia are convening to seek an end to more than two years of civil war. A major assault by President Bashar Al-Assad's forces on a rebel held town over the past week is shaping into a pivotal battle. It has drawn in fighters from Assad's Lebanese allies Hezbollah, justifying worry that a war that has killed 80,000 people would cross borders at the heart of the Middle East. Washington and Moscow have been compelled to revive diplomacy by developments in recent months, which include new reports of atrocities, accusations chemical weapons were used and the rise of Al-Qaeda-linked fighters among rebels. US Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov will meet privately in Paris Monday to discuss their efforts to bring Syria's warring parties together, US and Russian officials said. Russia said the Syrian government had agreed in principle to attend the planned peace conference, which could take part in Geneva in the coming weeks, and had “expressed readiness” to find a political solution. Under intense international pressure to resolve internal divisions so it can play a meaningful role in the talks, Syria's Western-backed opposition National Coalition met in Istanbul to elect new leaders and broaden its membership. Senior opposition figures said the coalition was likely to attend the conference, but doubted it would produce any immediate deal for Assad to leave power — their central demand. “We are faced with a situation where everyone thinks there will be a marriage when the bride is refusing. The regime has to show a minimum of will that it is ready to stop the bloodshed,” said Haitham Al-Maleh, an elder statesman of the coalition. There was more heavy fighting on Friday in Qusayr, a town controlling access to the coast which Assad's forces and Hezbollah allies have tried to take in a battle that could prove an important test of Assad's ability to withstand the revolt. Burhan Ghalioun, a strong candidate to become the new head of the opposition, said the coalition was likely to agree to go to Geneva because it did not want Assad to gain political advantage from the meeting. Other possible candidates include Ahmed Tumeh Kheder, a prominent opposition campaigner from the eastern province of Deir El-Zor, which borders Iraq's Sunni Muslim heartland; Louay Al-Safi, a professor who has taught in the United States; and acting coalition president George Sabra, a Christian who led protests early in the uprising. — Reuters