POLICE used tear gas on Monday to halt a march against building a controversial Atlanta-area police and firefighter training centre that opponents call Cop City.

More than 400 people marched about two miles from a park to the site in suburban DeKalb County, chanting “Stop Cop City” and “Viva, viva Tortuguita,” invoking the nickname of an activist who was fatally shot by state troopers while camping in the woods during a protest earlier this year.

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 centre site. 

Officers decided to deploy tear gas against the protesters.

Atlanta Police Chief Darin Schierbaum later said that the protesters had disobeyed orders to stop the march, noting they did not have a permit for it. 

He said the fact that the marchers showed up with gas masks was one indication they sought to provoke police.

Mr Schierbaum said: “This is not a group that has the best interests of Atlanta at heart. This is a group today that left Gresham Park prepared to reach the site, prepared to do harm, prepared to do destruction.”

Some protesters acknowledged that they wanted to enter the construction site as an act of civil disobedience, but disputed any intention of violence.

Community Movement Builders activist Kamau Franklin said: “The police continue to show themselves to be a group that is weaponised against the larger public, particularly the larger public that has the nerve to protest against police violence and police actions.”

Atlanta Mayor Andre Dickens and other supporters say that the 85-acre, $90 million (£73m) facility would replace inadequate training facilities and help the police department recruit and retain officers. 

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