Syrian opposition talks aimed at presenting a coherent front at an international peace conference to end the civil war are facing the prospect of collapse.
The failure of the Syrian National Coalition to alter its Islamist-dominated membership as demanded by its international backers and replace a leadership undermined by power struggles is playing into the hands of President Bashar al-Assad, whose forces are attacking a key town as his ally Russia said he would send representatives to the conference, coalition insiders said.
After two days of meetings in Istanbul, senior coalition players were in discussions late into the night after veteran liberal opposition figure Michel Kilo rejected a deal by Syrian businessman Mustafa al-Sabbagh, who is the coalition's secretary-general, to admit some members of Kilo's bloc to the coalition, the sources said.
Kilo has said that his group wants significant representation in the opposition coalition before it will join.
"There is a last-minute attempt to revive a kitchen-room deal. The coalition risks undermining itself to the point that its backers may have to look quickly for an alternative with enough credibility on the ground to go to Geneva," a senior opposition source at the talks said.
While the opposition remained wracked by differences, a major assault by Assad's forces and their Lebanese Hezbollah allies on a Sunni town held by rebels near the border with Lebanon over the past week was shaping into a pivotal battle.
The intervention of Shia Hezbollah is justifying fears that a war that has killed 80,000 people would cross borders at the heart of the Middle East.
"It is ironic that Lebanon's civil strife is playing itself out in Syria. The opposition remains without coherence and the regime is intent on taking back anything it promises with violence," said one diplomat.
The diplomat was referring to a deepening sectarian divide between Shia and Sunni Muslims in Lebanon, where Syrian troops were present for 29 years, including for most of the civil war that ended in 1990.
Assad belongs to Syria's minority Alawite sect, an offshoot of Shi'ism that has controlled Syria since the 1960s.
He has vowed to defeat what he calls terrorists and foreign agents behind the uprising, which began with months of peaceful protests and evolved into an armed revolt after months of military repression.