Protesters slam police for shooting unarmed black man in US

Demonstrators gathered late Tuesday night at the scene of yet another police shooting in the US. They came to protest against the police after an officer shot and killed an unarmed black man in El Cajon in southern California.

Protesters chanting "black lives matter!" and "hands up, don't shoot!" are accusing the officers of the unjustified killing of Alfred Olango, 30.

In Tuesday afternoon's incident in El Cajon, two officers responded to calls that an African-American man in his 30s was walking in traffic and "not acting like himself," El Cajon police said.

Witnesses report Olango seemed to be mentally ill and appeared to have had a seizure at the time he was shot dead by the police.

In less than two weeks, black men in Charlotte, North Carolina and in Tulsa, Oklahoma, have been shot dead by police, sparking protests. In Charlotte, rioting prompted the authorities to impose a state of emergency.

During a news conference hours after the shooting, El Cajon Police Chief Jeff Davis said two officers had responded to a call regarding a man walking in traffic. He refused their instructions to remove his hand from his pocket and then pulled out an object from his pants and pointed it at them, the department said in a statement.

The officers then simultaneously shot and tasered the man who died after being taken to hospital, the department said. No weapon was found on the scene.

The officers were placed on administrative leave, which is standard procedure in such incidents.

A few hours later, video footage emerged on social media purportedly showing the moments after the incident at the scene. In the video, a woman, who claimed to be the man's sister, is heard saying that she called the police.

"Oh my God. You killed my brother. I just called for help and ... you killed him," the unidentified woman said as she sobbed.

Protesters were asked to be patient as police investigate the incident.

"Now is a time for calm," Davis said at the news conference.

"I implore the community to be patient with us, work with us, look at the facts at hand before making any judgment."

According to data provided by The Guardian, this would be the 188th incident of a black male being fatally shot by US police officers. Similar deaths have added to a torrent of accusations over racial bias in US law enforcement and calls for greater police accountability for the killings of black people.