Police have arrested a teenager who is accused of attacking pro-Palestinian protesters at an encampment at the University of California, Los Angeles (UCLA).
The attack three weeks ago led to brawling that ended after more than two hours, when police cleared the site.
The arrest of Edan On, 18, appears to mark the first arrest of a counter-protester linked to the overnight campus chaos.
Mr On is reportedly the person, in widely shared pictures and video of the melee, seen wearing a white hoodie and mask and hitting protesters with a wooden pole.
Police have not identified the man they arrested by name but arrest records show that Mr On was taken into custody by UCLA police on Thursday morning.
He was detained at a business in Beverly Hills and is being held in a Los Angeles County jail.
He faces one felony charge of assault with a deadly weapon, according to the LA County Sheriff’s Department.
Mr On’s mother initially said her son was the person seen in videos in the white mask at the protest encampment, according to reporting by CNN earlier this month, although she later said he denied being there.
She said that Mr On was in his final year of high school and plans to join the Israeli military.
His family declined to comment to US media on Friday.
An official with the LA Sheriff’s Department told BBC News on Friday that he has been released on bond, pending trial.
According to US media, his bond was set at $30,000 (£24,000).
A letter from the UCLA Office of Campus Safety on Friday confirmed that detectives from the campus police force had assisted in making “their first arrest in the ongoing investigation into the April 30 assaults that occurred on our campus”.
UCLA “is committed to investigating all reported acts of violence and is actively working to identify the other perpetrators of violence associated with protest activities”, the statement continued.
It added that “those who inflicted violence on our community will be held accountable to the fullest extent of the law”.
The clashes on 30 April lasted for hours, and led to intense criticism of the university police force.
More than 200 pro-Palestinian protesters who did not leave the encampment were later arrested.
Earlier this week, the university removed its campus police chief after he was criticised for not halting the violence.
Universities around the US have seen protest movements spring up in opposition to the war in Gaza.
But the violence at UCLA shocked Americans.
It took place only hours after New York City police raided and cleared a Columbia University building taken over by students.
On Thursday, UCLA Chancellor Gene Block testified to Congress in Washington DC about the university’s response to the protests.
As he was speaking, protesters on campus erected a second encampment, barricaded access to buildings and committed acts of vandalism, the university said on Friday.
The protesters were told to leave or face arrest, and they “willingly dispersed” the university said, adding that no arrests were made.