A black man has been shot dead by police in the US state of Minnesota as protests continued over the police killing of a black man in Louisiana.
Philando Castile’s girlfriend live-streamed the St Paul incident’s aftermath, showing him covered in blood as an officer pointed his gun at him.
He was shot as he reached for his driving licence, she said.
It follows the death of Alton Sterling, who was shot dead by police during an incident in Baton Rouge on Tuesday.
Hundreds of people have protested for two nights over Mr Sterling’s killing.
The deaths follow a long line of high-profile incidents involving African-Americans dying at the hands of the police, igniting a national debate about the use of lethal force.
As news of the latest shooting spread, about 200 people protested outside the St Paul home of Minnesota Governor Mark Dayton, who later requested a federal investigation into the shooting.
In a statement on Facebook, President Barack Obama said all Americans “should be deeply troubled” by the two fatal shootings.
He said it was clear that they were not isolated incidents but “symptomatic of the broader challenges within our criminal justice system”.
Black US tennis player Serena Williams, who is playing at the Wimbledon tournament, also expressed her dismay at news of Mr Castile’s death, tweeting: “In London I have to wake up to this. He was black. Shot 4 times? When will something be done – no REALLY be done?!”
Transcript of St Paul shooting aftermath
Celebrities react to shootings
Show of support for victim’s girlfriend
Who are latest US police shooting victims?
Why do US police kill unarmed black men?
Cases where US police have faced charges over killings
When do US police use deadly force?
Mr Castile had been stopped in Falcon Heights, a suburb of St Paul, because the car had a broken rear light, the woman, identified in local media reports as Diamond Reynolds (or sometimes as Lavish Reynolds) said.
Before he was shot, he had told the officer that he was licensed to carry a concealed gun and had one in his possession, she said.
“You shot four bullets into him, sir. He was just getting his licence and registration, sir,” Ms Reynolds says in the video.
Philando Castile was a school cafeteria supervisor
A child, Ms Reynolds’s daughter, was also in the car at the time.
Police said an investigation was under way and the officer involved had been put on leave.
Mr Castile’s mother, Valerie Castile, told CNN that her son was just “black in the wrong place” and said there was “a silent war against African-American people”.
Later on Thursday, an emotional Ms Reynolds told protesters outside the governor’s house that she had filmed the incident so “the world knows that these police are not here to protect and serve us, they are here to assassinate us”.
Mr Castile, 32, worked as a cafeteria supervisor at a Montessori school. His cousin Antonio Johnson told the Star Tribune newspaper he was “immediately criminally profiled” because he was black.