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, according to authorities.

Fire officials responded to 26 Federal Plaza on Foley Square just before 4 p.m. after personnel found the menacing letters containing the mysterious substance in the 9th-floor mailroom of the Jacob K. Javits Federal Office Building, officials said. 

The historic address, also home to the US Department of Homeland Security, immigration court and other federal agencies, was swiftly evacuated as the fire department’s hazmat teams investigated. 

ICE agents detaining immigrants inside a New York City courthouse.Officials are still awaiting test results on the suspicious white powder. Getty Images

There were no reported injuries, officials said. 

“Right now, no threat remains to any employees or the public at this time,” Christopher Raia, Assistant Director in Charge of the FBI’s New York office, told reporters during a news conference Thursday night. 

“We are working to assess the potential threat. Sending threatening letters of this nature, whether real or a hoax, is a crime. It diverts valuable, limited law enforcement resources as you’ve all seen tonight.”

Police officers in tactical gear inside a courthouse.Officials said that there are no reported injuries. Getty Images

Test results are currently pending to identify the white powder. 

The envelopes will then be sent to the FBI’s Quantico lab in Virginia for further analysis as the agency launches its own probe.

“In the majority of my experience, most of these incidents turn out to be nothing. However, this matter is not going to be taken lightly and we will proceed like there is something to it,” Raia added. 

“But there is no indication at this point that there is danger to the public.” 

The investigation is ongoing.

The shocking incident, seemingly targeting ICE’s 9th-floor offices, comes two days after a federal judge ordered the agency to improve its immigration holding facility following complaints from jailed migrants over inhumane conditions.

Judge Lewis A. Kaplan ruled Tuesday in a lawsuit filed on behalf of detainees that the immigration agency must limit capacity, keep holding rooms clean, and provide sleeping mats in so-called hold rooms.

The lawsuit alleged dirty, foul-smelling, and overcrowded cells where detainees were denied soap, toothbrushes, and other basic hygiene and menstrual products. 

The Lower Manhattan building has become a hub for arrests as the Trump administration continues its aggressive crackdown on illegal immigration.

ICE facilities and officers have been targeted by violence since the administration ramped up arrests and deportations. 

Last month, 10 members of an armed mob were charged with attempted murder after opening fire on local cops, unarmed federal agents and detention workers at the Prairieland Detention Center near Dallas, Texas. 

One officer was shot in the neck when one suspect fired 20 to 30 rounds after the deranged group set off fireworks at the ICE facility and spray-painted cars parked at the building, according to the criminal complaint.