ATLANTA (NewsNation) — Police used tear gas and flash-bangs Monday to halt a march seeking to stop the construction of a police and firefighter training center in Atlanta.

More than 500 people Monday marched about two miles from a park to the site, which is just outside the Atlanta city limits in suburban DeKalb County.

A wedge of marchers, including some in masks, goggles and chemical suits intended to protect against tear gas, pushed into a line of officers in riot gear on a road outside the training center site. Officers pushed back and then responded with tear gas, with one protester throwing a canister back at officers.

Protests against the proposed training center — dubbed “Cop City” by opponents — have occurred for over two years. Georgia Attorney General Chris Carr obtained a sweeping indictment in August, using the state’s anti-racketeering law to target 61 protesters, characterizing them as “militant anarchists.”

Some marchers Monday retreated from the clash while others tried to wash away the effects of the tear gas. Dozens of protesters ran into the woods on the property where the training center is being built, then joined hands and exited the property. They and other marchers then retreated, with no apparent arrests. Vomiting and irritation from the tear gas were the only apparent injuries.

Protesters called the event “Block Cop City,” and events were held across the country to support Monday’s demonstration. It was the latest effort to stop construction, part of a protest movement that has galvanized environmentalists and anti-police protesters nationwide.

Supporters have said the 85-acre, $90 million facility would replace inadequate training facilities and help the police department recruit and retain police officers.

Opponents argue the facility could lead to greater police militarization and that its construction in the South River Forest will worsen environmental damage in a poor, majority-Black area.

Resistance to the project has at times sparked violence and vandalism. Prosecutors now characterize the protest movement as a conspiracy, saying it has led to underlying crimes, including possessing fire accelerants and throwing Molotov cocktails at police officers.

Most of those indicted in August on the racketeering charges had already been charged with other crimes in connection with the movement. RICO charges carry a sentence of five to 20 years in prison that can be added on top of the penalty for underlying acts.