International inspectors have started destroying Syria's stockpile of chemical weapons and the machinery used to create it, a United Nations official has revealed.

The inspectors are racing against a tight deadline to eliminate President Bashar Assad's chemical weapons programme within nine months.

The elimination was prompted by a chemical weapons attack in mid-August that killed hundreds of civilians on the outskirts of Damascus and brought a rare consensus at the UN.

A UN Security Council resolution agreed last month isays the first stage is to destroy Syria's capability to produce chemical weapons by November 1.

The official said that by the end of Sunday, a combination of both weapons and some production equipment would be put out of order.

"Today is the first day of the phase of destruction and disabling. Verification will also continue," said the official, who works alongside inspectors.

He spoke anonymously because of the sensitivity of the issue.

"The plan was that two types or categories of materials would be destroyed: one is equipment for making [weapons] - filling and mixing equipment, some of it mobile, and some it static. The other is actual munitions," he said. He could not confirm what specifically was destroyed, nor where the destruction took place.

An advance team of disarmament experts from the Organisation for the Prohibition of Chemical Weapons (OPCW) arrived in Syria in the past few days to set up the broader operation to dismantle and ultimately destroy the chemical programme, believed to include 1000 tonnes of toxic agents.

The UN Security Council resolution set the tightest timetable ever for the OPCW, to completely eliminate the programme by mid-2014.