The FBI is investigating a targeted “act of terrorism” after a man used a makeshift flamethrower and petrol bombs on a pro-Israel event in Colorado.
It happened as a group of people in Boulder were holding a walk to remember the Israelis still held hostage in Gaza.
A 45-year-old man was arrested and the FBI said he shouted “Free Palestine” as the attack on Pearl Street unfolded.
Six people aged 67 to 88 were injured – with some airlifted to hospital.
A large part of downtown Boulder was cordoned off as sniffer dogs and the bomb squad searched for potential devices.
However, police currently believe no one else was involved
Police chief Steve Redfearn said the attack happened around 1.26pm on Sunday and that initial reports were that “people were being set on fire”.
He said injuries ranged from “very serious” to “more minor”.
“When we arrived we encountered multiple victims that were injured, with injuries consistent with burns,” Mr Redfearn told the media.
Senior law enforcement officials told NBC News, Sky’s US partner, that at least one person was in a critical condition.
Mr Redfearn said a suspect – who the FBI named as 45-year-old Mohamed Soliman – had been taken into custody without incident.
The FBI’s Denver chief, Mark Michalek, said it was “clear that this is a targeted act of violence and the FBI is investigating this as an act of terrorism”.
The White House described the suspect as an “illegal alien” who had received a work permit under the Biden administration despite overstaying a tourist visa.
Boulder’s police chief said the attack happened as a “group of pro-Israel people” were peacefully demonstrating.
Brooke Coffman, a 19-year-old student, described seeing four women on the ground with burns on their legs. She said one appeared badly burned on most of her body and had been wrapped in a flag.
“Everybody is yelling, ‘get water, get water,'” Ms Coffman said.
A statement from Boulder’s Jewish community said “an incendiary device was thrown at walkers at the Run for Their Lives walk on Pearl Street as they were raising awareness for the hostages still held in Gaza”.
Colorado attorney general Phil Weiser said the group who were attacked gathered weekly on Pearl Street to call for the release of the remaining hostages held by Hamas.
Boulder is a university city of about 105,000 people on the northwest edge of Denver, in the foothills of the Rocky Mountains.
The attack follows the arrest of a Chicago-born man in the fatal shooting of two Israeli embassy employees in Washington DC two weeks ago.
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Tensions are simmering in the US over Israel’s war in Gaza.
There has been an increase in antisemitic hate crime, as well as moves by some supporters of Israel to brand pro-Palestinian protests as antisemitic.
President Trump’s administration has detained protesters without charge and pulled funding from elite universities that have permitted such demonstrations.
Senate Minority Leader Chuck Schumer, a prominent Jewish Democrat, was one of the first to comment on the attack.
He posted on X: “Less than two weeks after the horrific antisemitic attack at the Capitol Jewish Museum in DC – and after two relentless years of surging antisemitic attacks across the country – the Jewish community is once again shattered by pain and heartbreak.”
