An individual who police believe is a protester with a history of activity against the U.S. Immigration and Enforcement agency threw what appeared to be a smoke grenade outside a federal building in New York City on Monday.

Authorities said that the "makeshift incendiary device," which was thrown outside 26 Federal Plaza in Lower Manhattan, was made up of fireworks and a flammable liquid, WABC reported. 

The building has offices for the FBI's New York field office as well as an immigration court. 

The man ignited a fire and menaced pedestrians with a firearm, according to Bloomberg. He was pulling a cart that held "long guns," additional fireworks and other items, according to police. 

Officers secured the area, and the suspect was taken into custody. One person was treated for a minor injury sustained during the arrest, but declined further medical attention. 

The New York Police Department said a "found firearm" was tied to the incident, Fox News reported. Video footage shows U.S. Immigration and Enforcement and other federal agents on the scene. 

The NYPD Emergency Service Unit established a perimeter around the building, and the bomb squad was called in.