The governor of the north-central US state of Minnesota on Thursday denounced the shooting of a black man by a police officer during a traffic stop as racially motivated.
"Would this have happened if the drivers and the passengers were white? I don't think it would have," Governor Mark Dayton said in a press conference.
The US Justice Department was monitoring a state investigation of the shooting of Philando Castile, 32, near Minneapolis, Minnesota, days after the launch of a federal investigation into a similar incident in the southern state of Louisiana.
"The department is prepared, as necessary, to conduct further investigation and consider this matter under applicable federal law," it said in a statement.
Dayton has asked the Justice Department to begin an immediate independent investigation into Castile's killing.
Castile was shot four times by an officer late Wednesday as he tried to get out his wallet after being pulled over for a broken tail light, police said.
His fiancee, Diamond Reynolds, recorded the aftermath using Facebook Live, as Castile bled profusely while the officer continued pointing his sidearm at him. Castile later died at the county hospital.
During the traffic stop before the shooting, Castile informed police that he had a permit to carry a concealed weapon and was armed, Reynolds said.
Her 4-year-old daughter was in the back seat of the car during the entire incident.
Dayton stressed that state authorities were taking the incident very seriously and said it appeared that Castile had not done anything to provoke the police officer. He expressed horror that the man had not been given first aid on the scene and that Reynolds and been handcuffed and taken to the police station.
"Nobody should be shot and killed for their tail light being out. Nobody should be shot and killed in the seat of their car," he said.
The officer involved has been placed on paid administrative leave, said Jon Mangseth, interim police chief in suburban St Anthony, Minnesota.
Castile's death comes a day after the death of Alton Sterling, a 37-year-old black man shot by police in Baton Rouge, Louisiana, after officers responded to a complaint about a black male selling CDs and threatening the caller with a gun. The US Justice Department said Wednesday it would investigate Sterling's killing.
Both deaths sparked outrage on social media and calls by civil rights leaders and politicians to address the issue of police brutality against African-Americans.
"I am horrified that we are forced to confront yet another death of a young African-American man at the hands of law enforcement," Minnesota Senator Al Franken said. "They deserve nothing less than a full and independent investigation into Philando's death by the Department of Justice."
US President Barack Obama said that he has faith that the Justice Department will conduct a fair civil rights investigation.
He called for implementation of the recommendations made by the task force he assembled on community policing practices after the shooting death of Michael Brown two years ago in Ferguson, Missouri.
"Regardless of the outcome of such investigations, what's clear is that these fatal shootings are not isolated incidents," Obama said in a Facebook statement Thursday. "We can and must do better to institute the best practices that reduce the appearance or reality of racial bias in law enforcement."