A string of top diplomats met behind closed doors on Wednesday with Syria's divided opposition, in a last-ditch effort to break a deadlock in the National Coalition.
Dissidents say the chaotic meeting has been deadlocked by internal bickering as well as conflicting pressures from key backers of the revolt, Saudi Arabia, Qatar, France, Turkey and the United States.
These nations, some of which have conflicting visions for the opposition, sent in top representatives on Wednesday, as the meeting dragged into its seventh day, four days longer than was scheduled.
Turkish foreign minister Ahmet Davutoglu, US ambassador to Syria Robert Ford and a top French diplomat on Syria were at the meeting along with Saudi intelligence official Salman bin Sultan and top Qatari diplomat Khaled al-Attiyah.
Despite a week of marathon meetings and heavy criticism from rebels and activists inside Syria, the Coalition has failed to find common ground on key issues, including whether to take part in in a peace conference proposed by the United States and Russia.
"The Coalition really is at a make-or-break moment. If we fail to agree after this meeting, I don't know what will happen to the group," said a Coalition member who was present at the high-level meeting and spoke to AFP on condition of anonymity.
"There is so much mistrust. I really hope the problems get resolved. We should be on the same side," he added.
A Turkish foreign ministry official meanwhile insisted Davutoglu's nearly three-hour meeting with the divided dissidents did not aim to impose a specific formula to break the deadlock.
"The minister's visit is to meet with the Syrian opposition on behalf of the 11-nation core group of the Friends of Syria," he said.
"We wanted to deliver a message that we have full support for the Syrian opposition, we respect every decision they'll make in unity and we want to see the concrete results of their meeting as soon as possible," he told AFP on condition of anonymity.
After Davutoglu's departure, the Saudi and Qatari envoys stayed on for more talks.
Veteran secular Syrian dissident Michel Kilo, a Christian writer and rights activist who was voted into the Coalition and has been at the heart of debate this past week, was also present at the talks.
Saudi Arabia, which backed Kilo's bid to join the Coalition, wants the group to expand in order to water down the influence of the powerful Muslim Brotherhood.
Opponents supported by regional rival Qatar, including the Muslim Brotherhood, have resisted the Saudis' move.
A week into the meeting, dissidents have failed to agree on any key issues, chief among them the proposed peace conference that Washington and Moscow are trying to organise in Geneva next month.
The Istanbul meeting was also supposed to choose a new Coalition president, agree on an interim government and vote in new members to join the group.