Police and demonstrators have clashed for a second night in Wisconsin after the officers shot a black man on Sunday.
Jacob Blake is reportedly in a stable condition after officers shot him multiple times as he tried to get into a car in the city of Kenosha.
Protests erupted in the city soon after, and have now stretched into a second night.
Governor Tony Evers has called up the National Guard to aid local police.
In a press release, Governor Evers said the “limited mobilisation” – made at the request of local officials – was to help law enforcement “protect critical infrastructure” and make sure people can demonstrate safely.
“Every person should be able to express their anger and frustration by exercising their First Amendment rights and report on these calls to action without any fear of being unsafe,” he said. A curfew came into effect at 20:00 local time (01:00 GMT), to last until 07:00 on Tuesday.
The governor also called a special session of the state legislature on 31 August to discuss a package of laws announced earlier this year on accountability and transparency of the police.
Mr Evers announced the legislation in the wake of the police killing of George Floyd in the neighbouring state of Minnesota. His death in May highlighted police brutality and racism in the US and sparked protests around the world.
What’s the latest from Kenosha?
Reports suggest up to 200 members of the National Guard were to be deployed on Monday as demonstrators turned out for a second day.
Earlier in the day some protesters tried to force their way into Kenosha’s public safety building, demanding those officers involved in the shooting on Sunday be arrested. A door was broken off its hinges before officers in riot gear used pepper spray to disperse the crowd.
Later there was a confrontation at the county courthouse as the curfew came into effect. Some demonstrators threw objects at officers dressed in riot gear outside.
Hundreds of people marched on police headquarters on Sunday night to demonstrate against the shooting.
Vehicles were set on fire and protesters shouted “we won’t back down” as officers used tear gas to try to disperse the crowds.
Governor Evers also said there would be a special legislative session next week to discuss laws he announced earlier this year on police accountability.
Lawmakers “have failed to act” in the two months since he announced the “commonsense policies”, the governor tweeted.
“I am urging the Legislature to rise to this occasion and give this special session the urgent and productive effort this moment demands and that the people of Wisconsin deserve,” he wrote.
What do we know about the shooting?
Kenosha Police Department said the “officer involved shooting” happened shortly after 17:00 on Sunday. It added that officers had provided “immediate aid” to Mr Blake, who was taken to a hospital in Milwaukee in serious condition.
In video footage shared on social media, three officers can be seen pointing their weapons at a man identified as Mr Blake as he walks around a parked SUV. As he opens the door and leans into the car, one officer can be seen grabbing his shirt and opening fire. Seven shots can be heard in the video, as witnesses shout and scream.
The police said officers had been responding to a “domestic incident” but gave no details about what led to the shooting. It is so far unclear who called police and what happened before the video recording began.
Civil rights lawyers Ben Crump has announced he is representing Mr Blake’s family. In a statement released on Twitter he said the 29-year-old father of three “was helping to de-escalate a domestic incident” at the time.
Mr Crump said the officers’ “irresponsible, reckless, and inhumane actions nearly cost the life of a man who was simply trying to do the right thing”.
Wisconsin’s Department of Justice is investigating the incident. The officers involved have been placed on administrative leave and a petition calling for them to be charged has garnered tens of thousands of signatures.
Democratic presidential nominee Joe Biden on Monday released a statement calling for a “full and transparent investigation” of the shooting.
Governor Evers also condemned the shooting, saying Mr Blake “is not the first Black man or person to have been shot or injured or mercilessly killed at the hands of individuals in law enforcement in our state or our country.”
But the Democratic governor has faced criticism for this response. Pete Deates, head of Kenosha’s police union, said Mr Evers’ statement was “wholly irresponsible” and said people should wait until all facts are known. BBC News