SEVERAL people have been left with serious injuries after a “targeted terror attack” in Colorado – as the FBI launch an investigation.

Terrified witnesses reported seeing several people set on fire and a man holding a weapon, cops in Boulder have said.

The attack is said to have targeted pro-Israel protesters outside the Pearl Street Mall.

Boulder Police Chief Stephen Redfearn says many of the victims reported injuries consistent with burns to their skin.

The wounded conditions range from minor to “very serious” and an exact number is yet to be announced.

Officers responded as quickly as they could once being alerted of the carnage at around 1:26pm local time.

Mass evacuations were quickly ordered near to the crime scene.

It is unclear what weapon was used.

Unconfirmed reports stated petrol bombs may have been used by the suspect.

A man has since been arrested “without incident” and taken to a nearby hospital for treatment on his burns, cops said.

Investigators are still hunting for a vehicle of interest which was seen near to the mall at the time of the attack.

FBI Director Kash Patel posted on social media: “Our agents and local law enforcement are on the scene already, and we will share updates as more information becomes available.”

Mr Patel also described it as a terror attack.

Police in Colorado are yet to agree and say any motive is still unclear.