WASHINGTON (AP) — The head of the Justice Department says it is reviewing complaints about surveillance by the New York City Police Department of Muslim and Arab communities.

At a hearing before a House appropriations subcommittee, Attorney General Eric Holder said the department has not opened a formal investigation.

The Associated Press first reported that the New York police compiled lists of mosques and Muslim businesses it saw as potential security risks for reasons that included endorsing conservative religious views or having devout customers. The AP found that New York police has dispatched teams of undercover officers into minority neighborhoods as part of a human mapping program and has monitored daily life in bookstores, bars, cafes and nightclubs. Police have also used informants to monitor sermons in mosques even when there’s no evidence of wrongdoing.