Designation allows surveillance of sermons and worshippers, according to confidential police documents.
The New York Police Department (NYPD) has allegedly branded US mosques as “terrorist organisations” so it can monitor anyone who attends them.
This is according to confidential police documents leaked to the AP news agency.
Muslim groups say the labels are consistent with religious profiling by the NYPD and are calling on the US Department of Justice to investigate.
Al Jazeera’s Cath Turner reports from New York City.