Syria will take part in non-binding UN talks: FM

But says Syria can't implement any democratic political measures related to elections while terrorism is striking at home

Syria will take part in UN talks aimed at launching formal negotiations on ending its four-year war but will not be bound by their outcome, Foreign Minister Walid Muallem said today.

Muallem told the UN General Assembly that he understood the talks, proposed by UN envoy Staffan de Mistura, to be "mainly to exchange ideas" and non-binding.

He addressed the 193-nation assembly as Russian warplanes carried out a third day of air strikes in Syria, this time targeting the IS bastion of Raqa.

Russia launched its air war this week, saying it was responding to a request for help from President Bashar al-Assad to defeat the Islamic State group.

Taking a swipe at the US-led coalition that has been fighting IS jihadists for a year, Muallem said airstrikes were "useless" unless carried out in coordination with the Syrian army "the only force in Syria that is combating terrorism."

Russia and the United States have clashed over how to address the crisis in Syria with Moscow insisting that Assad's army must take part in the military campaign to defeat IS jihadists.

Washington is calling for Assad to step down and hold him responsible for the majority of the 240,000 deaths from the war.

The United Nations is making a third attempt for a peace settlement in Syria, led by Italian-Swedish diplomat Staffan de Mistura.

Four working groups have been established to tackle safety and protection, political and legal affairs, the military and counter-terrorism, and reconstruction.

"I would like to announce here that Syria agrees to participate in the four brainstorming committees of experts proposed by the special envoy Staffan de Mistura," said Muallem.

But the foreign minister made clear that fighting the Islamic State group was the government's immediate focus and declared that the "Syrian army is capable of cleansing the country of those terrorists."

"Syria cannot implement any democratic political measures related to elections, a constitution or the like, while terrorism is striking at home," he said.

No date has been set to start the preparatory talks, which are to take place in Geneva.