International experts have verified all but one of Syria's 23 declared chemical weapons sites after viewing a video presented by the Syrian government showing the destruction of a facility in the country's northern conflict- plagued city of Aleppo, a UN official said here Thursday.

The joint mission by the Organization for the Prohibition of Chemical Weapons (OPCW) and the United Nations, which is overseeing the destruction of Syria's chemical arsenal, visited 21 of the sites last month.

However, "the additional site inspected is in the region of Aleppo and was one of the two sites that could not be visited earlier due to safety and security reasons," said Farhan Haq, the acting deputy UN spokesman.

The Syrian government provided the joint mission with footage of the facility near Aleppo that confirmed the site has been dismantled and abandoned.

"The exact geographical location and the time of capture of the footage and images were fully authenticated," he said. "The site was confirmed as dismantled and long abandoned, with the building showing extensive battle damage."

Information about the Joint Mission in Syria is now available on a dedicated website launched Thursday. The website, http://opcw. unmissions.org, provides background information in English about the establishment of the joint mission, its mandate and its activities relating to the destruction of Syria's chemical weapons program.

"Available only in English so far, a version in Arabic is expected to follow at a later date," said the spokesman.