The current round of peace negotiations on Syria is due to end in Switzerland later on Friday, with little or no progress expected on core issues, BBC reports.
After a week of talks at the UN headquarters in Geneva, the opposing sides are still stuck on the question of how to proceed.
UN envoy Lakhdar Brahimi has said he hopes for more progress in next week's second round of talks.
He said he was "very, very disappointed" that a UN aid convoy was still waiting to enter the rebel-held Old City of Homs, where the US says civilians are starving.
Diplomats have said that a top priority is to keep the talks process going in the hope that hard-line positions can be modified over time.
More than 100,000 people have died since the uprising began in March 2011.
US and Russian officials - co-sponsors of the conference - are in Geneva advising the opposition and Syrian government delegations, their respective allies.
Both sides have agreed to use a 2012 document known as the Geneva Communique as a basis for discussions.
That agenda sets out stages to end the conflict, including a halt to fighting, delivery of aid and the setting up of a transitional government body.
UN Secretary-General Ban Ki-moon said on Thursday that the UN would "continue to explore every avenue for progress" in the Syria talks.