Tyre, which has been subjected to intense Israeli bombing in recent months, was founded around 4,700 years ago, and the city contains archaeological remains from the Roman era.
Two sites in the city have been on the World Heritage List since 1984: a Roman triumphal arch and a 1st-century hippodrome. In June, one of the sites was hit in an Israeli bombing.
"The site has been directly hit and sustained damage. Its conservation status is of concern, particularly given the risk of further attacks," UNESCO said on Wednesday.
The decision to include Tyre on the List of World Heritage in Danger was made at the organization's 48th meeting of the World Heritage Committee in Busan, South Korea.
