Members of the delegation of the Syrian Negotiation Commission (SNC) attend a meeting with United Nations Deputy Special Envoy for Syria Ramzy Ezzeldin Ramzy during the Intra Syria talks in Geneva, Switzerland December 1, 2017. REUTERS/Denis Balibouse

GENEVA (Reuters) - The Syrian government’s delegation returned to Geneva on Sunday for the resumption of talks with United Nations mediator Staffan de Mistura after more than a week’s absence, but Western diplomats voiced scepticism about its willingness to engage.

Bashar al-Ja’afari, Syria’s ambassador to the U.N. and chief negotiator in talks aimed at finding a political solution to end the nearly seven-year-old war, landed in a snowstorm on a flight from Beirut, a Reuters reporter on board said. Ja’afari declined to comment.

De Mistura convened an eighth round of separate talks with the government and unified opposition delegations on Nov. 28, focusing on constitutional reform as well as elections.

But Ja’afari arrived a day late and left after two days, saying the opposition had “mined the road” to the talks by insisting that President Bashar al-Assad could not play any interim role in Syria’s political transition.

De Mistura told reporters last Thursday that he would assess this week whether either side is trying to “sabotage” the process.

“The opposition has been extremely constructive and willing to get down to it,” a senior Western diplomat said. “They are in a difficult place while being criticized internally and pressured by the fact that the regime is bombing away in eastern Ghouta and other places.”

The diplomat told Reuters that the government’s failure to return as scheduled on Dec. 5 had been “a clear sign of not being interested in engaging in the political process”.

Russian President Vladimir Putin has suggested holding a Syrian congress in the Russian city of Sochi early in 2018. Diplomats see his plan as a bid to draw a line under the war and celebrate Moscow’s role as the power that tipped the balance of the war and became the key player in the peace process.