Demonstrators have set fire to a US police station after video emerged online showing a police officer kneeling on the throat of black man who later died.

A Minneapolis Police Department spokesman said the protesters broke into the 3rd precinct station, which has become the scene of numerous demonstrations by those angered at the video showing 46-year-old George Floyd's arrest.

The spokesman said police abandoned the building "in the interest of the safety of our personnel" while livestream video showed the protesters breaking in, setting the building ablaze and igniting fireworks as fire alarms blared and sprinklers ran.

Minnesota Governor Tim Walz earlier on Thursday called in the National Guard at the Minneapolis mayor's request, but it was not immediately clear when and where the reserve force was being deployed and troops were not seen at protests in the city or nearby St Paul.

Businesses in both cities have boarded up their windows and doors in an effort to prevent looting, with Minneapolis-based Target announcing it was temporarily closing two dozen area stores.

Minneapolis has shut down nearly its entire light-rail system and all bus service until at least Sunday out of safety concerns.



It is time to rebuild. Rebuild the city, rebuild our justice system, and rebuild the relationship between law enforcement and those they're charged to protect. George Floyd's death should lead to justice and systemic change, not more death and destruction.

— Governor Tim Walz (@GovTimWalz) May 28, 2020

The demonstrations began on Tuesday after Mr Floyd died the previous day in a video in which Officer Derek Chauvin, who is white, kneels on his neck until he slowly stops talking and moving. The 3rd Precinct covers the portion of south Minneapolis where Floyd died.

Chauvin, whose driveway was splattered with red paint and the graffiti "murderer", has not spoken publicly since Mr Floyd's death and his lawyer did not respond to calls seeking comment.

He and the other three officers involved in Mr Floyd's arrest were fired on Tuesday.

Minneapolis City Council records showed that Chauvin moonlighted as a bouncer at a downtown Latin nightclub and was among a group of six officers who opened fire on a stabbing suspect in 2006 after a chase that ended when the suspect pointed a sawn-off shotgun at them.

The suspect, Wayne Reyes, was hit multiple times and died, and kinh nghiệm du lịch sapa a grand jury decided the use of force was justified.

Two years later, Chauvin shot Ira Latrell Toles as he was responding to a domestic dispute.

Online city records also showed that 17 complaints have been filed against Chauvin during his 19-year service.

Sixteen complaints were closed with no discipline, and the remaining complaint generated two letters of reprimand, with one apparently related to the use of a squad car dashboard camera.

The records do not include any details on the substance of the complaints.

Less is known about the other three officers involved in Mr Floyd's arrest.

Online court records indicated the officer who stood guard at the scene, Tou Thao, was sued in federal court in 2017 for alleged excessive force.

According to the lawsuit, Lamar Ferguson claimed Mr Thao and his partner stopped him as he was walking to his girlfriend's house in 2014 for no reason and beat him up. The city ultimately settled the lawsuit for 25,000 dollars (£20,000).

City records show six complaints have been filed against Mr Thao, five of which were closed with no discipline and one remains open.

Thomas Lane joined the force as a cadet in March 2019 according to online city records and no information about J Alexander Kueng's service history was immediately available.