United States Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov have agreed to push again for an international conference aimed at ending Syria's civil war.
They met with the United Nations envoy on Syria in Geneva, where they are trying to confirm a Russian plan to remove Syria's chemical weapons and avert US military action, Reuters reports.
The two men have agreed to try to make progress on a broader effort to end a conflict that has divided the Middle East and world powers.
They will meet again in about two weeks, during the United Nations General Assembly in New York. They also hope progress in Geneva, overnight, on a chemical weapons disarmament deal will help revive plans for a peace conference.
"We are committed to trying to work together, beginning with this initiative on the chemical weapons, in hopes that those efforts could pay off and bring peace and stability to a war-torn part of the world," Mr Kerry told a joint news briefing.
Mr Kerry earlier cautioned that the United States could still carry out a threat to attack President Bashar al-Assad in retaliation for the poison gas attack thought to have killed 1,400 people last month if Washington is not satisfied with Syria's response.
UN special envoy Lakhdar Brahimi, who also represents the Arab League, says working to remove chemical weapons from Syria will form an important element in efforts to hold new peace talks, following an earlier failed attempt at Geneva last year.
As the diplomacy continued in Switzerland, Mr Assad's forces were on the offensive against rebel-held suburbs of Damascus, opposition activists and residents said.
Warplanes and artillery were bombing and shelling, notably in the Barzeh neighbourhood, where activists said there were also clashes on the ground.