Russian President Vladimir Putin said on Tuesday that Syria was "very actively" cooperating with chemical weapons inspectors and suggested that Indonesia join international peace talks on the crisis.

"Doubts about whether the Syrian leadership would adequately respond to the decision taken on chemical weapons -- these doubts did not bear out," Russian news agencies quoted Putin as telling reporters at a regional summit in Indonesia.

"The Syrian leadership has very actively joined this work and is acting in a transparent manner, helping international agencies," said Putin.

"I hope that this work will continue at the same pace, in the same spirit."

Putin added that Moscow would welcome large Muslim nations such as Indonesia joining Syria peace talks that the United States and Russia hope will take place in Geneva in mid-November.

"We believe it is possible to expand the number of (conference) participants by including such big Muslim states like Indonesia," Putin said. "In my opinion, it would be quite natural and we'd welcome it."

Putin said he had discussed the progress of Syria's disarmament with US Secretary of State John Kerry, who was standing in at the Indonesian summit for President Barack Obama, who was grappling with a budget crisis in Washington.

The UN Security Council endorsed a Russian-US disarmament plan for Syria last month, after a chemical weapons attack near Damascus on August 21, in which hundreds died.

The United States blames the attack on Syrian President Bashar al-Assad's forces, although Russia believes the rockets with the deadly gas were fired by rebels who were trying to draw Western powers into the conflict.

Putin stressed that Russia and the United States were largely in agreement over how to deal with Syria, despite Moscow's continued backing for Assad.

"Our disagreements about Syria were mostly technical in nature," said Putin.

"We generally have the same goals aimed at stabilising the situation, achieving democracy, creating peaceful conditions for civilians.