Video report by ITV News Washington Correspondent Robert Moore
Donald Trump has vowed to deploy more national guards to Kenosha as violence and unrest continue to spill onto the streets after the police shooting of Jacob Blake.
Kenosha, in Wisconsin, has seen three straight nights of unrest since Blake was wounded by police over the weekend with his children in the car.
During protests on Tuesday, two people were shot dead in a possible vigilante attack, while a third person suffered injuries.
Teenager Kyle Rittenhouse, of Antioch, Illinois, has been arrested and charged with murder.
The US President tweeted he will be "sending federal law enforcement and the National Guard" to Kenosha to "restore law and order".
The city has been rocked by unrest sparked by the police shooting of Jacob Blake, who was "left paralysed" after he was shot multiple times - apparently in the back.
The Milwaukee Bucks have boycotted their NBA play-off fixture against the Orlando Magic in protest over police shootings, with both other matches scheduled for Wednesday reportedly also set to be called off in a sign of growing outrage in the States.
Two people were killed on Tuesday night in an attack allegedly carried out by a young white man who was caught on mobile phone video opening fire in the middle of the street with a semi-automatic rifle.
“I just killed somebody,” he could be heard saying at one point during the shooting rampage that erupted just before midnight.
In the wake of the killings, Wisconsin Governor Tony Evers authorised 500 members of the National Guard to support local law enforcement around Kenosha, doubling the number of troops sent in.
The governor’s office said he working other states to bring in additional National Guard troops and law officers.
One victim was shot in the head and the other in the chest, Sheriff David Beth told the Milwaukee Journal Sentinel.
A third person suffered gunshot wounds not believed to be life-threatening.
“We were all chanting ‘black lives matter’ at the gas station and then we heard, boom, boom, and I told my friend, 'that’s not fireworks,’” 19-year-old protester Devin Scott told the Chicago Tribune.
"And then this guy with this huge gun runs by us in the middle of the street and people are yelling, ‘he shot someone, he shot someone’ and everyone is trying to fight the guy, chasing him and then he started shooting again.”