SAMARRA, Iraq—The construction of a training center and barracks for police is threatening the Great Mosque of Samarra, a precious Iraqi historical site added to Unesco’s list of endangered world heritage sites this summer, reports the Guardian.

Archaeologists from Unesco and elsewhere fear that the compound will become a target for insurgents and that the construction and operation of the barracks will damage the mosque and the Samarra Archaological City, the ninth-century remains of the capital of the Abbasid dynasty.

Work is continuing on the project, which was undertaking without consultation with Unesco. Officials of the organization said the dire situation in Samarra had prevented them from taking any measures to protect the site.