The man who allegedly threw homemade Molotov cocktails at a gathering of people at a demonstration in Boulder, Colorado, showing their support for Israeli hostages in Gaza, was charged with a federal hate crime, the police said.
The attack injured 12 people.
According to the authorities, Mohamed Sabry Soliman said he would do it again.
Authorities also said Soliman had overstayed his US tourist visa and had been planning the assault for a year.