Oren Segal from the Anti-Defamation League (ADL) told the BBC News Channel the attack was "completely shocking" and an "attack on the Jewish community".

More needs to be done to stop a "rising tide of hate" against Jews, he said citing the recent attack in Washington which left two Israeli embassy staff members dead.

"What we need to do is also figure out a way to stop normalising the type of rhetoric that we know animates this activity," he added.

The ADL is an organisation that "fights all forms of antisemitism", according to its website.

On Thursday, the ADL warned that Jewish communities in the US faced a "concerning environment of unprecedentedly high threats".

Image source, Reuters

Boulder Mayor Aaron Brockett says he is saddened and outraged by the "appalling attack".

"I want to be clear that violence and hatred have no place here.

"Attacks like these seek to strike terror in people's hearts and divide us from one another, but Boulder will stand strong together," he wrote in a post on X.

We are learning more about the suspect, Mohamed Sabry Soliman. The 45-year-old is an Egyptian national, government officials have confirmed to the BBC's broadcast partner, CBS in Colorado.

In 2022, Soliman arrived in California on a non-immigrant visa that expired in February 2023, multiple sources have told CBS News. He had recently been living in Colorado Springs.

According to the FBI, the suspect shouted "free Palestine" as he carried out the attack using a "makeshift flamethrower" and an "incendiary device".

Authorities have also said they were "fairly confident" that they have the lone suspect in custody.

Image source, Reuters

The Jewish holiday of Shavuot, celebrating the giving of the Torah to the Jewish people, began at sundown on Sunday night and lasts for the next two days.

Many Jewish community groups have scheduled religious and cultural events over the coming days, such as candle lightings at night, holiday meals and Torah reading sessions.

Boulder police say they are aware of those events and ensuring there are "resources there at those events to ensure that people are able to go about their business safely".

They are also urging the public to report any suspicious activity or behaviour.

Christal Hayes
Reporting from Los Angeles

The incident that unfolded in Colorado today is the second high-profile attack in less than two weeks in the US suspected to be related to the ongoing war in Gaza.

Six people were injured in Boulder after authorities said a man threw Molotov cocktails and used a makeshift flamethrower on demonstrators who gathered in solidarity with Israeli hostages.

The FBI says the man shouted "free Palestine" during the attack.

On 21 May, less than two weeks ago, a man opened fire on people who had gathered for a networking event at the Capital Jewish Museum in downtown Washington DC.

A young couple who worked for the Israeli embassy were shot dead by the man, who shouted "free, free Palestine" as he was arrested, police say. Elias Rodriguez has been charged with first-degree murder in that case.

Image source, Reuters

Some more details about the investigation have just emerged.

The FBI says it is conducting "court-authorised law enforcement activity" at a location in El Paso County, Colorado.

"The FBI is at a location in El Paso County, CO, conducting court-authorised law enforcement activity related to the attack on the Pearl Street Mall in Boulder," the FBI Denver branch wrote on X.

"As this is an ongoing investigation, no additional information is available at this time."

Police in Boulder have also issued an update on road closures in the Boulder area, saying many of the roads around the attack had been reopened.

A video circulating online appears to show people trying to help those injured in the wake of the attack.

Smoke can be seen rising above a group of people gathered in a grassy area.

Screams and yelling can also be heard as people run and move around the area.

People were "running and screaming" from the scene of the attack, reports Andrew Haubner of CBS News, the BBC's partner in the US.

Standing just outside the evacuation perimeter, Haubner says witnesses describe seeing the suspect who was alleged to have aerosol cans, was "lighting them and throwing them at individuals", leaving a "large burn scar mark" on the pavement.

One local business owner ran to aid those injured by the flames, bringing water to "put out the burns", Haubner said.

Image source, Reuters

Let's recap what we just learned from the press conference.

The FBI says the attack in Boulder, Colorado was a "targeted act of violence", and they are investigating it as an "act of terrorism".

What happened?

The suspect, Mohamed Sabry Soliman, 45, is accused of using a "makeshift flamethrower" and an "incendiary device" in the attack. The FBI says he shouted "free Palestine".

A group had gathered for a "regularly scheduled, weekly, peaceful event", which the BBC understands was a Run for Their Lives event, an organisation which raises awareness for Israeli hostages still held in Gaza.

Police say they are "fairly confident" that they have the lone suspect in custody. There's no evidence the suspect is connected to a wider group.

Who are the victims?

There are six victims, aged between 67 and 88.

All of them have been taken to hospitals with burns and other injuries.

At least one of the victims is seriously injured.

What's happening now?

Authorities say they won't hold another press conference today.

Police say their teams are still working in the area.

The district attorney for Boulder County said: "We are fully united 100% in making sure the charges we bring hold the attacker fully accountable."

The Boulder Courthouse will remain closed on Monday.

Image source, Getty Images

Michael Dougherty, the district attorney for Boulder County, echoes the FBI saying "we are in the very early stages here".

He says that all agencies are working together "to hold the attacker fully accountable".

"That is my promise," he adds.

"We are fully united 100% in making sure the charges we bring hold the attacker fully accountable."

Police have said there won't be any more updates tonight.

Police chief Stephen Redfearn also said he was "fairly confident" that there was "not an additional suspect at large".

He said that the police had received reports of "differing descriptions", but after speaking to witnesses, the police believe they have the lone suspect in custody.

The press conference has now finished.

Before ending proceedings, the FBI took questions and was asked for more details about the suspect.

Special agent Mark Michalek said the suspect was in custody and there was no evidence at this time that he was connected to a wider group.

He added those checks were "ongoing".

"We are early in the investigative process and both teams will be working side by side collaboratively."

Image source, Getty Images

The police chief says victims in the attack range in age from 67 to 88.

He says at least one of the victims was seriously injured and is in critical condition. He said among the six who were hurt, some had more minor injuries.

"Our thoughts are heavily focused on their recovery," he adds.

He says the suspect is also injured and was taken to hospital.

Image source, Getty Images

Redfearn thanks first responders who rushed to the scene where a man was "throwing Molotov cocktails, and using other devices to hurt people".

He said they then took the man into custody, and began to support the victims.

We've just heard from police chief Stephen Redfearn.

He thanks the FBI for their "swift response" to the attack.

Redfearn says there are multiple teams still working in downtown Boulder "clearing that area for devices".

He adds that there are canine and bomb squads in the area, and that they want to make sure the area is safe before it is reopened.

The Boulder Courthouse will remain closed on Monday.

Image source, Reuters

The FBI says it's treating the attack as a suspected act of terrorism, confirming there are six victims.

The suspect, according to FBI's special agent Mark Michalek, was heard to have yelled "Free Palestine" during the attack. He was named as Mohamed Sabry Soliman.

The victims are aged between 67 and 88, Michalek adds in the press conference.

A press conference being held by the FBI and Boulder police has just started in Denver now. Stay tuned here - and watch the live stream above.

Image source, EPA

Homeland Security Secretary Kristi Noem has said her department is working with "interagency partners, including the FBI", and would share more information when it becomes available.

"We are praying for the victims and their families. This violence must stop."

Image source, Getty Images

Israel's foreign minister, Gideon Sa'ar, has just released a statement saying he is "shocked" by the incident and calls the attack "pure antisemitism".

"Shocked by the terrible antisemitic terror attack targeting Jews in Boulder, Colorado," he wrote on X.

"This is pure Antisemitism, fueled by the blood libels spread in the media. I spoke with our Ambassador in the US and our Consul General in LA.

"I pray for those who were wounded in the attack."

While the FBI is treating the incident as "an act of terror", the Boulder County Police Department have avoided labelling the incident as such and have urged people not to speculate.

We should have more details soon as the FBI holds a press conference at 18.30 local time (01:30 BST).

We have more details on the evolving situation on the ground as the investigation continues. Emergency officials issued the first evacuation order at 14:39 local time (20:39 GMT), warning people away from an area three blocks wide between Pine Street and Walnut Street in central Boulder.

Less than an hour later, another order came expanding the evacuation zone to the L-shaped area we highlighted earlier.

At 16:10 this nearly doubled in size, sweeping downtown to 9th Street where it remains.

We will update you if this changes again.

Image source, Google