The world's chemical weapons watchdog has postponed Sunday's meeting to discuss a Russia-US plan to destroy Syria's arsenal.

"The meeting of the Executive Council of the OPCW in regard to Syria, scheduled for Sunday has been postponed," the Organisation for the Prohibition of Chemical Weapons said in a statement Friday.

"We will announce the new date and time in this space as soon as possible," the Hague-based organisation added.

Diplomatic sources said that a draft text to be discussed at the meeting had not yet been agreed upon by the United States and Russia.

The OPCW has already postponed the meeting several times this week.

The Hague-based OPCW's 41-member Executive Council is due to discuss the plan agreed last weekend in Geneva in a bid to avert US-led military strikes on Syria, blamed by the West for a deadly chemical weapons attack in August.

The OPCW is charged with implementing the Chemical Weapons Convention, which Syria asked to join amid growing calls for military action against Damascus.

Its Executive Council is made up of ambassadors from different nations with diplomatic representations in The Hague.

Russia backs the Damascus government in blaming opposition rebels for the August 21 poison gas attack near the Syrian capital in which hundreds of people died.

The plan says that President Bashar al-Assad's regime will hand over a list of its chemical weapons and facilities by Saturday, and that all will be destroyed by mid-2014.

However, a defiant Assad said in an interview on Wednesday that the task would take at least a year and cost a billion dollars.