Thirty-five people were detained in Atlanta on Sunday after a violent protest at the site of a new police training center, police said.

The Atlanta Police Department described “a group of violent agitators” who “used the cover of a peaceful protest” to clash with authorities in “a coordinated attack on construction equipment and police officers.”  

“They changed into black clothing and entered the construction area and began to throw large rocks, bricks, Molotov cocktails, and fireworks at police officers. The agitators destroyed multiple pieces of construction equipment by fire and vandalism,” police said.

Thirty-five were arrested, and police said Sunday night that detentions were ongoing. Officials didn’t specify how many of those detained were also arrested or what charges were brought. 

Protests have been ongoing over the proposed Atlanta Public Safety Training Center, which activists have dubbed “Cop City” and would reportedly include a “mock village” for cops to practice raids.

“This was a very violent attack that occurred this evening. Very violent attack. This wasn’t about a public safety training center, this was about anarchy and this was about the attempt to destabilize,” Atlanta Police Department chief Darin Schierbaum told reporters. “This was not a protest, this was criminal activity.”

Georgia Gov. Brian Kemp (R) released a statement saying that “domestic terrorism will NOT be tolerated in this state.”