A US teenager charged with shooting three people amid racial justice protests in Kenosha, Wisconsin, last year took to the stand in his own defense on Wednesday.

Kyle R, who was 17 at the time of the shootings, argued that the victims attacked him and he fired in self-defense.

During his testimony, he sobbed so hard at one point that the judge declared a break.

The defense made a motion for a mistrial after Kenosha County Judge Bruce Schroeder repeatedly scolded the prosecution for attempting to introduce evidence he previously had deemed inadmissible.

The now-18-year-old faces a misdemeanor charge of underage possession of his weapon along with five felony counts.

He could get life in prison if convicted of the most serious charges. He has pleaded not guilty to all counts.

The case has divided many in the United States, with some viewing the shootings as a justified response to the chaos in Kenosha. Meanwhile, others view the incident as a symbol of a gun culture run amok.

Key points from today's testimony

Kyle R. told the court that he traveled to the city with an AR-15-style semi-automatic weapon and a medic bag to protect property from rioters who had set fires and ransacked businesses in the two preceding nights.

He claimed he only used his weapon only after being attacked, saying: "I used deadly force to stop the threat that was attacking me."

Kyle R. began to cry when his attorney began asking him to detail his encounter with one victim, Joseph Rosenbaum, who he shot four times.

"I didn't notice Mr. Rosenbaum until he came out from behind the car and ambushed me," Kyle R. testified, before breaking down, prompting the judge to call for a break.

"I didn't intend to kill them, I intended to stop the people who were attacking me," Kyle R. said.

Meanwhile, prosecutors tried to paint Kyle R. as a vigilante who carried an assault-style weapon into a volatile melee and wanted to use it. They asked him about his ammunition and penchant for playing violent video games.

The jurors were sent out of the room just before Kyle R. began testifying while the judge explained his right to remain silent and the potential risks of testifying.

What happened in Kenosha?

Protests erupted in Kenosha on August 23, 2020, in the wake of the shooting of Jacob Blake, a Black man, by police.

By the night of the shootings, Kenosha had experienced two nights of tumultuous protests. Several businesses were burned to the ground and there were incidents of looting. Police used rubber bullets and tear gas to control crowds, which included men wearing military-style gear and carrying rifles who confronted the sometimes-violent protesters.

kmm/sms (Reuters, AP)