A team of international experts have begun the process of destroying Syria's chemical gas arsenal.

Witnesses said the experts left their Damascus hotel in the early hours of this morning for an unknown location.

According to declassified French intelligence, Syria's chemical arsenal includes more than 1,000 tonnes of chemical agents.

Also included are precursor chemicals for the production of mustard gas and the nerve agents sarin and VX.

The team consists of experts from the Organization for the Prohibition of Chemical Weapons in The Hague and United Nations personnel assisted them in their work. 

The mission, which Washington and Moscow hammered out after a chemical weapons attack in Damascus last August, prompted US threats of air strikes against the Syrian government.

The mission is expected to continue until at least mid-2014.

The Syrian government and the rebels blame each other for the chemical incident in a Damascus suburb in which more than 1,400 were killed.

The US and other Western countries say a report by UN investigators indirectly implicates government-allied forces for the attack.

More than 100,000 people have died in Syria's conflict,which began in early 2011.

The conflict began peaceful demonstrations seeking more democracy but has deteriorated into sectarian civil war.

Earlier, UN peace envoy for Syria Lakhdar Brahimi said that it is not certain that peace talks will take place in mid-November in Geneva as planned.

Asked if the conference was a certainty, he said in an interview with TV5 television and RFI radio: "No, this is not a certainty. I am trying to invite...I am encouraging everybody to come to Geneva in the second half of November."

Mr Brahimi said on Tuesday that the meeting was "not 100% certain".