The 41-floor office building is home to ICE's New York City field office, as well as the FBI's New York field office and an immigration court. It has made headlines and been the site of frequent protests over ICE operations in the city amid the Trump administration's crackdown on undocumented immigrants.

The five envelopes were sent to the FBI's headquarters in Quantico, Virginia, for testing, according to authorities.

The FBI is probing five letters containing white powder found in the ICE Enforcement and Removal Operations mailroom at 26 Federal Plaza in Lower Manhattan. The discovery prompted evacuations, though no injuries were reported.