PORTLAND (AP) — One man was arrested and one 40 mm less lethal round was deployed after a group gathered outside the Portland, Oregon, Immigration and Customs Enforcement building on Wednesday night, police said.

KOIN reports the large group began gathering outside the ICE building shortly before 10 p.m. Portland police say the crowd blocked traffic and set a dumpster on fire, which they eventually pushed in front of the building. Federal officers then emerged to push the crowd back in order to allow Portland Fire and Rescue crews to extinguish the flames.

According to the Portland Police Bureau, the crowd began firing off rock-like projectiles at federal officers around 11:30 p.m. Portland police stepped in once again to help disperse the crowd, using the less lethal round. Police initially said they used crowd control munitions but said later Thursday they were not used.

A 20-year-old man was arrested on charges of riot, second-degree disorderly conduct and attempted assault on a public safety officer.