"We have done nearly 50 per cent of the verification work of the facilities that have been declared to us," Malik Ellahi, a political advisor on Syria for the Organisation for the Prohibition of Chemical Weapons, told journalists in The Hague.
Despite the progress, Ellahi said security remained a concern for the unprecedented mission in war-torn Syria, with mortar and car bomb attacks around the inspectors' Damascus hotel. "One of the things that is of concern is of course the security situation," said Ellahi, who advises OPCW Director-General Ahmet Uzumcu.
"There have been a number of incidents over the last few days which gives some cause for concern." The OPCW said on Wednesday that its inspectors had checked 11 out of 20 sites identified by Damascus and destroyed chemical weapons equipment at six sites.
The organisation, which last week was awarded the Nobel Peace Prize, and the UN currently have about 60 experts working in Syria to eradicate chemical weapons, around a month after the OPCW accepted President Bashar al-Assad's application to join the Chemical Weapons Convention, in a bid to stave off a possible Western military strike.
Syria formally joined the convention on Monday. So far Syria has won rare praise for its cooperation with the inspectors, but the UN has stressed that key deadlines in the destruction of Syria's chemical weapons should be met.
OPCW destroyed chemical weapons equipment at six sites in Syria
This included verifying Syria's disclosed chemical weapons, identifying key equipment, destroying production facilities and starting the destruction of Category 3 chemical weapons by November 1.
Inspectors have until June 30 next year to complete the destruction of Syria's chemical arsenal. The United States threatened a military strike after an August 21 chemical weapons attack near Damascus in which hundreds of people died.
Under a disarmament plan that has been given added force by a UN Security Council resolution, Damascus now has until mid-next year to get rid of its reported stocks of sarin, mustard and VX gas. Syria must give the OPCW a plan for destroying its estimated stockpile of 1,000 tonnes of chemicals by October 27 -one month after the Security Council Resolution. By November 15, the OPCW will have set out a detailed plan with a timetable for the destruction of actual chemicals.