Russian Foreign Minister Sergei Lavrov, left, and Syrian Foreign Minister Walid Moallem during their meeting in Moscow on Friday. (Maxim Shipenkov/European Pressphoto Agency)

Syria’s opposition coalition was at risk of collapse Friday as international pressure mounted on the deeply divided body to attend landmark peace talks next week that many regime opponents fear will only reinforce President Bashar al-Assad’s hold on power.

In a renewed attempt to ease those concerns, Secretary of State John F. Kerry stressed the U.S. commitment to a transitional government that would pave the way for democratic elections and said the United States was not prepared to realign itself with Assad to fight terrorism.

A Syrian government offer to discuss a cease-fire in the contested northern city of Aleppo further intensified the pressure on the Syrian Opposition Coalition, which had been scheduled to vote Friday on whether to attend the talks.

Instead, the group, meeting at a secret location on the outskirts of Istanbul, postponed a vote until Saturday amid disputes over procedures. The skirmishing exposed the extent of the coalition’s failure to present a coherent alternative to Assad’s rule since it was formed more than a year ago.

“We recognize the coalition could fall apart,” said a senior member who spoke on the condition of anonymity because of the sensitivity of the subject. “We are in the intensive care unit.”

He and several other figures in the 125-member body predicted that the coalition would eventually agree to send a delegation to the negotiations, which will be launched at a gathering of world powers in the Swiss town of Montreux on Wednesday, then continue Friday in Geneva with the first direct talks between the opposition and the regime since the conflict began three years ago.

The coalition has no choice, said the senior member, if it is to retain relevance as the only internationally recognized representative of the Syrian opposition.

But the decision represents a dilemma for the loosely configured assembly of opposition figures who came together under international pressure to form what had once been envisaged as a potential alternative to Assad’s regime, but is now being asked to talk peace with it.

“This is a tough vote,” said Khalid Saleh, the coalition’s spokesman. “The victims are being asked to talk to the killers.”

The coalition’s ineptitude has cost it the support of most ordinary Syrians as well as a majority of the armed rebel groups, making it unclear who exactly the coalition will represent if it does attend the talks.

Not going would mean losing the support of the coalition’s last remaining constituents, however: the Western allies that helped foster the group’s creation. The conference is central to the Obama administration’s policy of encouraging a negotiated settlement to Syria’s brutal war, and diplomats acknowledge that there is no alternative plan.

“The decision on Geneva is a big deal for us. We will not be happy if they say no,” said one Western diplomat in Istanbul, speaking on the condition of anonymity.

Friday’s failure to vote centered on a dispute over whether the coalition’s founding principles, which state that there should be no negotiations with Assad, will have to be amended to enable attendance at Geneva. That would require a two-thirds majority of the members, which can’t be mustered because 45 of them walked out this month.

The disagreements have been compounded by intense rivalry for influence between Saudi Arabia and Qatar, the opposition’s chief financial backers. Most of the 45 members who withdrew are allied with Qatar, and Western diplomats have been pressuring Qatar to persuade them to return, coalition members say.

The United States, backed by Britain and France, has also exerted great pressure on coalition members to agree to attend, diplomats and coalition members say, offering a combination of threats to withhold aid and inducements to provide more of it.

Kerry warned Friday that additional pressure on Assad might be exerted if he fails to negotiate in good faith. The United States is “not out of options” to apply pressure on Assad, Kerry said, apparently referring to the fitful U.S. effort to provide weapons and supplies to rebels.

Kerry also rejected suggestions that the United States would switch the focus of the talks from a negotiated transition of power to the issue of terrorism at a time when the influence of radicals linked to al-Qaeda is on the rise. He said Assad has “purposefully” facilitated the rise of extremism to present himself as a Western ally against radicals.

“He’s been doing this for months — trying to make himself the protector of Syria against extremists, when he himself has even been funding some of those extremists,” Kerry said. He accused Assad of “purposefully ceding some territory to them in order to make them more of a problem so he can make the argument that he is somehow the protector.”

The Syrian government has repeatedly made it clear that it is not prepared to negotiate a transition of power at the Geneva talks. But after meeting in Moscow with Russian Foreign Minister Sergei Lavrov, Syrian Foreign Minister Walid al-Moualem proposed a cease-fire in Aleppo and said the government would be willing to encourage prisoner exchanges and greater access for humanitarian aid.

The offer was unlikely to affect the coalition’s willingness to attend, because of fears that the Geneva conference would lose sight of the opposition’s goal of replacing Assad, its supporters said.

Gearan reported from Washington. Suzan Haidamous in Beirut contributed to this report.