The United States has informed the UN Security Council that it has neutralized about 60 percent of Syria's most toxic chemicals.

Mark Lyall Grant, the British ambassador to the UN and the current president of the Security Council, said that the US made the report after a video-conference briefing by Sigrid Kaag, who heads the international effort to rid Syria of its chemical weapons.

He said Kaag reported that a meeting was held in Beirut on earlier Tuesday to work out methods to destroy the 12 chemical production facilities that Syria has declared. She said it will take about six months to complete.

Lyall Grant said he reported to the closed council meeting that Britain will complete its destruction of Syrian chemical precursors intended for the production of chemical weapons and hydrochloric acid "in the course of this week."

"So, good progress on the destruction of chemicals outside Syria," he said.

Syria agreed to surrender its chemical arsenal last year when the US threatened missile strikes in retaliation for a chemical attack on a rebel-held suburb of Damascus. The attack is believed to have killed more than 1,000 people.

In early July, some 600 metric tons of Syria's most toxic chemicals were transferred onto the US cargo vessel MV Cape Ray in the Italian port of Gioia Tauro. The ship moved into international waters and began the two-month process of destroying the chemicals.

New allegations

Lyall Grant said the US informed the council that once it has neutralized all the chemicals, the residue will be sent to Germany and Finland for final disposal.

He said Kaag, who heads the joint mission of the United Nations and the Organization for the Prohibition of Chemical Weapons, also briefed the council on the ongoing discussions about discrepancies in the Syrian government's initial declaration of its chemical weapons and precursor chemicals.

Kaag said a lot of technical questions need to be addressed, and an OPCW team plans a further visit to Damascus in September, Lyall Grant told journalists.

The material handed over by Syria included mustard gas and precursors for the nerve gas sarin. But questions remain over whether Syrian President Bashar al-Assad is hiding undeclared poison gases or attacking rebels with chlorine - a toxic industrial gas that is not specifically classified as a chemical weapon.

Lyall Grant said council members raised questions about allegations of further use of chlorine-based explosive devices in recent weeks.

PHOTO CAPTION

The U.S. started destroying Syria's chemical weapons Monday. About 600 metric tons of material is on the MV Cape Ray in international waters in the Mediterranean Sea.

Aljazeera