A contentious week-long first round of Syrian peace talks ended on Friday with no progress towards ending the civil war and the government delegation unable to say whether it will return for the next round in 10 days.

Darkening the atmosphere further, the United States and Russia clashed over the pace of Syria's handover of chemical arms for destruction. Washington accused Damascus of foot-dragging that put the plan weeks behind schedule, and Moscow - President Bashar al-Assad's big power ally - rejected this.

The Obama administration said it was working with partners to ratchet up pressure on Syria to accelerate the process, but stopped short of threatening any action if Damascus did not get the chemical weapons deliveries back on track.

The Russian government said Assad was acting "in good faith" in carrying out last year's international chemical disarmament agreement and a June 30 deadline for eliminating the poison gas agents remains viable.

U.N. mediator Lakhdar Brahimi, who has tirelessly pursued a peace deal that other diplomats consider "mission impossible", said the opposition delegation would be back on February 10, but President Bashar al-Assad's delegates had told him they would have to check with Damascus before agreeing to return.

"They didn't tell me that they are thinking of not coming. On the contrary, they said that they would come but they needed to check with their capital," Brahimi told a news conference.

Brahimi listed 10 simple points that he felt the two sides agreed on in the talks and said he thought there was more common ground than the sides recognized.

But neither side has budged an inch from their main positions: the opposition wants the talks to focus on a transitional administration it says will remove Assad from power; the government wants to talk about fighting "terrorism" - a word it uses to refer to all its armed foes.

"Progress is very slow indeed, but the sides have engaged in an acceptible manner," Brahimi said.

Syrian Foreign Minister Walid al-Moualem blamed the lack of tangible results on what he called the immaturity and narrow composition of the opposition delegation and their "threats to implode" the talks, as well as blatant US interference.

"There are huge divides between (the opposition delegation)and what happening on the ground in Syria. They are not in touch with what is taking place in Syria ... and have no control over anybody on ground," Moulem told reporters.

The Friends of Syria, an alliance of mainly Western and Gulf states that back Assad's foes, faulted the Syrian government for the lack of diplomatic headway.

"The regime is responsible for the lack of real progress in the first round of negotiations. It must not further obstruct substantial negotiations and it must engage constructively in the second round of negotiations," they said in a statement.

US State Department spokesman Edgar Vasquez said the Syrian government "continues to play games" with its non-committal stance to future talks while the opposition had shown it was serious in pledging to return to the table.

"The people of Syria are watching and will determine who truly has their best interests at heart. The Syrian people - who have suffered so much - deserve constructive engagement now and in the next round," Vazquez said.

Expectations had always been low for a breakthrough on political issues at the talks, the first between Assad's representatives and his foes in an almost three-year-old conflagration that has killed 130,000 Syrians and driven a third of the population from their homes.

The sides could not even achieve more modest goals, such as an agreement to allow aid convoys into Homs, Syria's third largest city, where thousands of civilians are trapped with no access to food or medicine.

"Homs was extensively discussed, although unfortunately there has been no breakthrough yet," Brahimi said.

Underscoring the relentlessness of the carnage, the Syrian Observatory for Human Rights, a Britain-based monitoring group, said 1,870 people had been killed during the week of talks, including 450 civilians and 40 who died from inadequate access to food and medicine in areas besieged by government troops.

With few achievements on substance, diplomats say the priority now is just to keep the talks process going in the hope that rigid positions can be modified over time.-Reuters