A US man was broadcasting a video of himself via Facebook Live when he was shot and killed on Wednesday, with the live-stream capturing the shooting and witnesses' reaction.

The Chicago man, Antonio Perkins, 28, inadvertently filmed and broadcast his own murder about 8.45pm Wednesday local time.

The Facebook Live video shows Mr Perkins broadcasting selfie-style on his smartphone and chatting, when a dozen gunshots suddenly ring out in quick succession.

The video failed to capture whoever was shooting.

Mr Perkins immediately drops the phone, and the stream then captures panicked voices reacting to the attack.

"Oh my God!" a woman can be heard yelling.

"Call the police! Hurry up!" a man says.

"Tony, you're good Tony," says another woman, talking to the victim.

Police said Mr Perkins died from gunshot wounds to the neck and head.

Detectives have made no arrests in their ongoing investigation.

Officials have said Mr Perkins was a documented gang member, but his acquaintances told Chicago televsion station WGN that he was no longer in a gang and that he was likely not the intended target of the shooting.

"Stop judging us like that. His life really did matter," one woman told WGN.

At least 13 other people were wounded in shootings in the city on the same day a tally by the Chicago Tribune suggestes.

Police said there have been some 269 murders in the city so far this year, which is a staggering 49 percent increase from the same period a year ago.

"We must end the killing fields," civil rights leader Jesse Jackson said.

Mr Perkins' shooting follows the shooting deaths of 49 people at a gay nightclub in Orlando, Florida, on Monday.

The killer, Omar Mateen, used a pistol and a Sig Sauer MCX rifle - an assault weapon originally designed for US Special Operations forces - to kill dozens and injured more than 50 people.

There has been much debate in the US about the role of assault rifles, automatic and semi-automatic weapons, and whether they have a place in American society.

Under considerable political pressure, the US Senate is expected to take up several gun-control measures next week.

Mr Perkins' live-streamed shooting also came as Facebook was dealing with the killings of a French police officer and his partner a day earlier, with the attacker having used Facebook Live to issue threats.

Facebook said it was cooperating with French authorities and that it treated "takedown requests by law enforcement with the highest urgency".

"We do understand and recognize that there are unique challenges when it comes to content and safety for Live videos," a Facebook spokeswoman said.