A team of disarmament inspectors began the process of destroying Syria's chemical weapons and production facilities on Sunday, a source in the international mission told AFP.
The source said members of the team from the UN and The Hague-based Organisation for the Prohibition of Chemical Weapons (OPCW) "have left for a site where they are beginning verification and destruction."
"Today is the first day of destruction, in which heavy vehicles are going to run over and thus destroy missile warheads, aerial chemical bombs and mobile and static mixing and filling units," the source, who spoke on condition of anonymity, added.
An OPCW official in The Hague said earlier this week that all "expedient methods" would be used to render Syria's production facilities unusable.
He said the methods could include the use of explosives, sledgehammers, or pouring in concrete.
The team of inspectors arrived in Damascus on Tuesday to begin the process of verifying details of the programme that were handed over by the Syrian government.
"Phase one which is disclosure by the Syrians is ending and we are now moving towards phase two, verification and destruction and disabling," the mission source said.
The team is in Syria under the terms of a UN resolution that enshrined a US-Russian agreement for President Bashar al-Assad's regime to turn over its chemical weapons for destruction.
The deal was hammered out in the wake of a 21 August sarin attack on the outskirts of Damascus, which the United States blamed on Assad's government -- a charge it denies.
Washington threatened military action in response to the chemical attack, but a strike was averted after the US-Russia deal was agreed.
Under the UN resolution on the agreement, Syria's chemical weapons arsenal is to be destroyed by mid-2014.