More than 20 people are facing domestic terrorism charges after dozens attacked the site of a police training centre under construction in a wooded area outside Atlanta where one protester was killed in January.

Atlanta is building a $90 million Public Safety Training Centre meant to boost preparedness and morale after George Floyd's death in 2020.

Flaming bottles and rocks were thrown at officers during the protest at the site dubbed 'Cop City', where 26-year-old environmental activist Manuel Esteban Paez Teran, or "Tortuguita," was shot dead by officers during a raid at a protest camp in January. Police have said that Tortuguita attacked them, a version that other activists have questioned.

The site has become the flashpoint of ongoing conflict between authorities and protesters who've joined forces to protest a variety of causes. Among them: People against the militarisation of police; others who aim to protect the environment; and some who oppose corporations who they see as helping to fund the project through donations to a police foundation.

Atlanta Police Chief Darin Schierbaum said at a midnight news conference on Sunday that pieces of construction equipment were set on fire in what he called "a coordinated attack" at the site.

Protesters threw rocks, bricks, Molotov cocktails, and fireworks at police, officials said. In addition, demonstrators tried to blind officers by shining lasers into their eyes, and used tyres and debris to block a road, the Georgia Department of Public Safety said on Monday.

Officers used nonlethal enforcement methods to disperse the crowd and make arrests, Schierbaum said, causing "some minor discomfort."

Along with classrooms and administrative buildings, the training centre would include a shooting range, a driving course to practice chases and a "burn building" for firefighters to work on putting out fires. A "mock village" featuring a fake home, convenience store and nightclub would also be built for rehearsing raids.

Opponents have said that the site would be to practice "urban warfare," and the 34-hectare training centre would require cutting so many trees that it would be environmentally damaging.

Many activists also oppose spending millions on a police facility that would be surrounded by poor neighbourhoods in a city with one of the nation's highest degrees of inequality.

Many of those already accused of violence in connection with the training site protests are being charged with domestic terrorism, a felony that carries up to 35 years in prison. Those charges have prompted criticism from some that the state is being heavy-handed.

More protests are planned in coming days, police said.