GENEVA (AP) — The head of Syria's government delegation on Friday blasted the opposition for statements made ahead of the current round of talks in Geneva, saying there can be no progress in light of such "provocative and irresponsible" statements relating to President Bashar Assad's future.

Speaking to reporters in Geneva, Bashar Ja'afari said his team will be leaving Geneva on Saturday, and that Damascus will decide whether the delegation would return Tuesday to continue the talks.

The U.N.'s Syria envoy Staffan de Mistura said Thursday that the current round of peace talks is to run through Dec. 15, with a weekend break. Speaking at the first news conference since talks began Wednesday with the arrival of the Syrian government envoys, he cited a "serious and professional" atmosphere between the opposition and government delegations, and pointed to a lack of trust as "the biggest obstacle."

He touted an unspecified "12 points" in the works that could lead to a "shared vision of what Syria could look like" after 6-1/2 years of war that has claimed at least 400,000 lives.

But Ja'afari on Friday painted a bleak picture of the talks.

He strongly criticized the opposition for its so-called Riyadh 2 communique, issued at the end of a conference in Saudi Arabia to unify the opposition ahead of the Geneva talks.

In that communique, the opposition said it was ready for talks with the Syrian government delegation "without preconditions," suggesting flexibility it was no longer insisting that President Bashar Assad step down as a precondition for talks. However it said that Assad would need to step down for any political transition to succeed in Syria.

Ja'afari described the communique as "a desperate attempt to take us back to square zero" and said that as long as it's out there "we cannot move forward."

He said the communique did not take into consideration the reality on the ground in Syria, which has changed in the past two years in the government's favor. "The Syrian government is the strong side. Our army is winning."

"As long as this provocative communiqué is there this means that we cannot move forward."

Ja'afari also criticized de Mistura in his comments.

He said that the government delegation had put forward in March a 12-point plan which he said de Mistura had kept tucked "in his pocket."

He added that de Mistura had put forward his own plan during this round without consulting with the Syrian delegation.

Mroue reported from Beirut.