The FBI is investigating an attack in Boulder, Colorado, FBI director Kash Patel announced. Boulder police say multiple people were injured in the attack.

Colorado governor Jared Polis said that he is “closely monitoring” the situation, adding: “My thoughts go out to the people who have been injured and impacted by this heinous act of terror. Hate-filled acts of any kind are unacceptable.”

However, Boulder police, in a news conference on Sunday evening, said they were “not calling it a terror attack at this time”.

The Boulder police chief Stephen Redfearn said the department received calls at about 1.26pm local time of a man with a weapon in downtown Boulder near the courthouse and people being set on fire.

When police responded, they found people with injuries consistent with burns. A suspect was pointed out to officers and that person was taken into custody and then to the hospital with minor injuries.

The chief only said that multiple people had been injured in the attack and their injuries ranged from “very serious” to more minor.

Redfearn said the police were investigating “a vehicle of interest” on the scene, which is closed off.

He asked for patience during the investigation as well as empathy for the victims of the attack. “This act is unacceptable,” he said.

The downtown area is a walking pedestrian mall, and police said there had been a peaceful protest by a group of pro-Israel people but that they were still investigating whether that group had been targeted.

“It would be irresponsible of me to speculate on motive this early on,” Redfearn said.

Redfearn said he understands the tensions and issues in the US and that police react accordingly – which could include additional security and other measures – once they had ascertained a clear motive.

Boulder’s Jewish community center released a statement shortly after the news conference, saying that a group of people had been participating in the Run for Their Lives walk. According to the local chapter, the group hosts walks in downtown Boulder every Sunday. Run for Their Lives is an organization that sponsors events calling for the immediate release of the hostages held by Hamas.

“Our hearts go out to those who witnessed this horrible attack, and prayers for a speedy recovery to those who were injured,” the statement from Boulder JCC said. “When events like this enter our own community, we are shaken. Our hope is that we come together for one another.”