The gunfire was reported just before midnight, and Sheriff David Beth said one victim was shot in the head and another in the chest, the Milwaukee Journal Sentine l reported. The third victim's wounds were not believed to life-threatening.

He said that investigators had reviewed footage of what happened and that he was confident a man would be arrested soon.

Beth told the Journal Sentinel that armed people had been patrolling the city's streets in recent nights, but he did not know if the gunman was among them.

"They're a militia," Beth said. "They're like a vigilante group."

Cellphone video of at least two of the shootings that was posted online shows what appears to be a white man with a semi-automatic rifle jogging down the middle of a street as a crowd and some police officers follow him. Someone in the crowd can be heard asking "What did he do?" and another person responds that the man had shot someone.

The man with the gun stumbles and falls, and as he is approached by people in the crowd, he fires three or four shots from a seated position, hitting at least two people, including one who falls over and another who stumbles away to cries of "Medic! Medic!"

A witness, Julio Rosas, 24, said that when the gunman stumbled and fell, "two people jumped onto him and there was a struggle for control of his rifle. At that point during the struggle, he just began to fire multiple rounds and that dispersed people near him."

"The rifle was being jerked around in all directions while it was being fired," Rosas said.

In the cellphone footage, as the crowd scatters, the gunman stands up and continues walking down the street as police cars arrive. The man puts up his hands and walks toward the squad cars, with someone in the crowd yelling at police that the man had just shot someone, but several of the cars drive past him toward the people who had been shot.

Protester Devin Scott told the Chicago Tribune that he witnessed one of the shootings.

"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,'" said Scott, 19. "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."

Scott said he cradled one of the lifeless victims in his arms, and a woman started performing CPR, but "I don't think he made it."

At a news conference earlier Tuesday, Ben Crump, the lawyer for Blake's family, said that Blake was shot multiple times by police on Sunday and that it would "take a miracle" for him to walk again. He called for the officer who opened fire to be arrested and for the others involved to lose their jobs.

The shooting of Blake -- apparently while three of his children looked on -- was captured on cellphone video and ignited new protests over racial injustice in the U.S. just three months after the death of George Floyd at the hands of Minneapolis police touched off a wider reckoning on race.

Kenosha police have said little about what happened, other than that they were responding to a domestic dispute. They have not said why the officers opened fire or whether Blake was armed, and they have not disclosed the race of three officers who were on the scene.

The 29-year-old Blake underwent surgery Tuesday, according to Crump, who added that the bullets severed his spinal cord and shattered his vertebrae. Another attorney said there was also severe damage to organs.

Blake's father, also named Jacob Blake, told the Chicago Sun-Times that his son had eight holes in his body. At a news conference, he said police shot his son "seven times, seven times, like he didn't matter."

"But my son matters. He's a human being and he matters," he said.

Blake's mother, Julia Jackson, told CBS "This Morning" in an interview that aired Wednesday that she feels as if she is in a "bad dream" and that it felt "unreal" that her son's name has been added to the list of Black people who were shot by police.

"Never in a million years did I think we would be here in this place. Him being alive is just a miracle in itself," she said.

During the latest round of unrest Tuesday, police fired tear gas for the third straight night to disperse protesters who had gathered outside Kenosha's courthouse, where some shook a protective fence and threw water bottles and fireworks at officers lined up behind it.

Wisconsin Gov. Tony Evers called in up to 250 members of the National Guard and declared an emergency ahead of Tuesday night's violence. The night before, crowds destroyed dozens of buildings and set more than 30 fires downtown.

"We cannot allow the cycle of systemic racism and injustice to continue," said Evers, who is facing mounting pressure from Republicans over his handling of the unrest. "We also cannot continue going down this path of damage and destruction."

Anger over the shooting has spilled into the streets of other cities, including Los Angeles and Minneapolis, the epicenter of the Black Lives Matter movement this summer following Floyd's death.