PARIS (AP) — UNESCO says about a third of the ancient city of Aleppo has been destroyed during the war in Syria.

The United Nations cultural organization conducted an emergency mission in Aleppo from between Monday and Thursday this week to assess damage at the World Heritage Site and reported "extensive damage" at the Great Umayyad Mosque, the Citadel and other historic buildings.

UNESCO said in a statement that "60 percent of the old city of Aleppo has been severely damaged, with 30 percent totally destroyed."

UNESCO envoys also met with Aleppo council members and non-governmental organizations and proposed that the ancient city should be declared an "emergency zone."

Pro-government forces recaptured Aleppo in December, ending rebels' four-year hold on parts of Syria's once largest and most important city.