Federal authorities are investigating after envelopes containing an unidentified white powder were found at a government building in New York City that houses an Immigration and Customs Enforcement office, officials said Thursday.

Five envelopes containing a suspicious white powder were discovered at New York’s Immigration and Customs Enforcement field office in Manhattan Thursday afternoon – prompting first responders to evacuate the federal building,

New York City’s 26 Federal Plaza building, which houses the Department of Homeland Security (DHS) and U.S. Immigration and Customs