Sergei Lavrov and John Kerry have met in Zurich to reach a consensus on who can join the negotiations. The UN-brokered talks are expected to take place within the next few days.
Lavrov told reporters in Zurich on Wednesday both he and Kerry dismissed the idea of waiting until February to begin the peace talks, which were first announced toward the end of last year.
The UN-mediated negotiations - the start of an 18-month political transition for the war-torn country - are set to begin on January 25.
Some observers expected them to be stalled as the US and Russia butted heads over which rebel groups should be allowed to participate. Moscow, a close ally of Syrian leader Bashar al Assad's regime, considers some of the US-backed rebels as terrorists.
Diplomacy, not war
Kerry also appealed to Russia to ensure that Assad allows aid to reach civilians in need. Humanitarian convoys have delivered food and other essential supplies to several blockaded towns this month, including Madaya, where an estimated 40,000 people are said to be suffering from hunger.
Kerry left the meeting with Lavrov to attend the World Economic Forum in Davos, where he will also meet with other world leaders including Israeli Prime Minister Benjamin Netanyahu.
blc/kms (Reuters, AFP, AP)