Asked whether the U.S.is prepared to accept Assad's continued rule until Syria's next scheduled presidential election in 2021 as reported by The New Yorker magazine, Nauert denied the claim.
On Monday, the Syrian government delegation returned to Geneva for a meeting with the United Nations special envoy Staffan de Mistura.
Repeating the format of the seven previous rounds of negotiation, de Mistura will meet separately with the delegations. "But the peace must be won - and for the peace to be won, it's necessary to have the courage to push the government also to accept that there must be a new constitution and new elections".
The Syrian opposition claims the government delegation to the Geneva peace talks is coming up with new conditions, making it hard to move forward.
Resolution 2254 adopted in December 2015 urges UNSC member states to support efforts to introduce ceasefire and calls for talks between the Syrian government and opposition.
The Syrian opposition delegation headed by Nasr al-Hariri announced that it was aiming for the removal of President Bashar al-Assadfrom participation in the preparation of the political settlement and planned to engage his negotiators in serious and direct talks. Therefore, the return of the delegation of the Syrian Government leaves only a few days to negotiate. At the start of the latest round, the delegations at one point sat just meters (yards) away from one another in separate rooms.
The Syrian united opposition delegation at the Geneva talks has expressed hope that Russia is working toward achieving progress at the ongoing negotiations, after Russian President Vladimir Putin said that he was hoping for Russia to help build a peaceful life and political process in Syria jointly with Turkey and Iran.
The civil war in Syria has killed hundreds of thousands of people and driven more than 11 million from their homes.