The incident occurred as demonstrators marched to demand justice for unarmed black man killed by police.

A sheriff’s vehicle in the US state of California has hit an activist as protesters continued their near-daily rallies, calling for justice for Stephon Clark, an unarmed black man killed by police.

Video of the incident shared on Twitter shows the police vehicle accelerating as a protester walks in front of the car. The protester is thrown to the ground.

The Sacramento Sheriff’s office confirmed in a statement sent to Al Jazeera that a collision did occur between a sheriff’s vehicle that was “travelling at slow speeds” and a protester “who was walking in the roadway”.

“As protesters approached both of the marked vehicles, they began yelling while pounding and kicking the vehicles’ exterior,” the statement said. “As one of the Sheriff’s Deputies was driving, a collision occured involving the Sheriff’s patrol vehicle and a protester who was walking in the roadway.”

The statement added that the pedestrian sustained minor injuries.

The incident occurred as demonstrators marched to demand justice for Clark, a 20-year-old father of two who was killed by police on March 18.

Police officers involved in the shooting death say they believed Clark was holding a gun as they shot at him more than 20 times in his grandmother’s backyard. It was later revealed that the young man was only holding a mobile phone.

His killing set off a wave of demonstrations from Sacramento to New York City, reigniting calls to end what many call the systemic racism among US police forces.

On Friday, it was revealed that Clark had been struck eight times, mostly in the back, by police, according to an independent autopsy, commissioned by Clark’s family.

‘Own your responsibility’

Member’s of Clark’s extended family spoke at Saturday’s rally, saying “nothing seems to change” when it comes to how police treat people of colour.

The “situation seems to happen quite often, that someone who looks like me isn’t going home,” Curtis Gordon, Clark’s uncle, told the rally, local media reported.

“You really can’t internalise that unless you live it,” he was quoted as saying, adding that the police officers involved in Clark’s killing “must become accountable”.

“You must own your responsibility,” he said.

Curtis Gordon speaks at a rally aimed at ensuring Clark’s memory and calling for police reform [Rich Pedroncelli/AP Photo]

The killing of Clark comes amid years of national outrage over what activists and others call institutionalised racism among US police.

The Washington Post’s Fatal Force database counted more than 980 people police killings in 2017. The Guardian documented more than 1,090 police killings the previous year.

Nearly a quarter of those killed in 2016 were African Americans although the group accounts for roughly 12 percent of the total US population.

According to a watchdog group The Sentencing Project, African American men are six times more likely to be arrested than white men.

People of colour make up around 67 percent of the 2.2 million people held in US prisons and jails.

These disparities, particularly the killing of African Americans by police, has prompted the rise of the Black Lives Matter movement, a popular civil rights movement aimed at ending police violence and dismantling structural racism.

On Friday, a white police officer who fatally shot Alton Sterling, a black man in the southern US state of Louisiana, in 2016 was fired, police said. The sacking came just days after the state’s district attorney said it would not be pressing charges against the two officers involved.