The United States and Russia are "very pleased" with progress in destroying Syria's chemical weapons stocks, US secretary of state John Kerry said on Monday. He offered some rare, if qualified, US praise for Syrian president Bashar al-Assad.

Kerry, speaking at a press conference with Russian foreign minister Sergei Lavrov, said the Assad regime deserved credit for its speedy compliance thus far with the UN security council resolution calling for the elimination of the weapons. But Kerry stressed Assad was not yet off the hook.

"Let me be crystal clear," Kerry said, "we're very pleased with the pace of what has happened with respect to chemical weapons."

He noted that experts had started the process of destroying the stockpiles on Sunday, just over a week after the United Nations security council and the international chemical weapons watchdog acted.

"I think that was a terrific example of global co-operation, of multilateral efforts to accomplish an accepted goal and they have moved with equal speed to get on the ground in Syria and begin the operations," he said.

"I think it is also credit to the Assad regime for complying rapidly as they are supposed to," Kerry said. "We hope that will continue. Now, I am not going to vouch today for what happens months down the road. But it is a good beginning and we should welcome a good beginning."

Kerry and Lavrov met on the sidelines of the Asia-Pacific Economic Co-operation summit (Apec) on the Indonesian island of Bali.

Lavrov said the Assad regime, an ally of Russia's, was co-operating fully. He stressed that the Western- and Arab-backed opposition must also comply and must ensure that chemical weapons not fall into the hands of extremists. Russia has accused the opposition of being behind the chemical weapons attack on 21 August that most countries blame on the regime.

"The responsibility is not only on the Syrian government, but also on the opposition and all the states in this sphere should of course not allow these weapons to fall into the hands of non-state actors," Lavrov said.

Kerry and Lavrov said they continued to make progress on preparations for an international conference to help set up a transitional government for Syria. The United Nations has said it would like to host the meeting in Geneva in mid-November. The meeting has been repeatedly delayed but Kerry and Lavrov said they hoped the rough date would hold.

Lavrov said the Syrian government had agreed to take part in the conference and urged the US and other supporters of the opposition to convince Assad's foes to attend. The opposition is splintered and has been unable so far to produce a delegation that could go to Geneva.