THE HAGUE - The downfall of Syria's Bashar al-Assad, found to have used chemical weapons against his own people on multiple occasions during the civil war, creates an opportunity to rid the country of banned munitions, diplomatic sources said on Monday.

The Organisation for the Prohibition of Chemical Weapons (OPCW) said it was following the situation in Syria with "special attention" to chemical weapons-related sites and had reminded Syria, through its embassy, of its continued obligation to declare and destroy all banned chemical weapons.

A team at OPCW has spent more than a decade trying to clarify what types of chemical weapons Syria still possesses, but has made little progress due to obstruction by Assad's government, it said.

"To date, this work has continued, and the Syrian declaration of its chemical weapons programme still cannot be considered as accurate and complete," the OPCW statement said.

A diplomatic source said Assad's government had been "playing cat and mouse with us for years" and that "we are convinced that they still had an ongoing programme."

"It costs millions and millions of dollars without making any progress," said the source, speaking on condition of anonymity. "So it really is a great opportunity now to get rid of (chemical weapons) for good. This is the moment."

Security guarantees will need to be arranged before any deployment by OPCW inspectors. That would require contacting new power brokers in Syria, possibly rebel forces in the alliance that toppled Assad, such as Hayat Tahrir al-Sham, a former al Qaeda affiliate labelled a terrorist group by some governments.

Past missions have not been free of risk. Members of a United Nations-OPCW mission to Syria were hit by explosives and AK-47 fire while trying to reach the site of a chemical attack in the northern town of Kafr Zita...