Washington DC - US Attorney General Merrick Garland warned Monday of increasing threats from "domestic violent extremists" amid growing attacks against minority groups, as he vowed a full investigation into the shooting of three men of Palestinian descent.

Police said a man had been arrested in connection with the wounding of the three students – Hisham Awartani, Kinnan Abdel Hamid, and Tahseen Ahmed – in Burlington, Vermont, as authorities probe what they believe was a "hate-motivated crime."

Burlington Police Chief Jon Murad said the suspect, 48-year-old Jason Eaton, was expected to appear before a judge Monday.

Garland said the Department of Justice was closely monitoring the impact that the Israel-Gaza war may have in "inspiring foreign terrorist organizations, home-grown violent extremists and domestic violent extremists both here in the United States and abroad."

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"There is understandable fear," Garland said, as the US experiences a "sharp increase" in threats and attacks against Jewish, Muslim, and Arab communities across the country since October 7, when Hamas militants in the Gaza Strip launched a deadly raid on Israel, sparking a brutal war.

The FBI and other federal agencies "are investigating the tragic shooting of three men of Palestinian descent in Vermont. That investigation, including whether this is a hate crime, is ongoing," Garland said in remarks delivered in New York city.

The Justice Department "is remaining vigilant in the face of the potential threats of hate-fueled violence and terrorism," he said.

In Burlington, police searched Eaton's apartment, outside which the shooting took place on Saturday.

Evidence seized there "gave investigators and prosecutors probable cause to believe that Mr Eaton perpetrated the shooting," Murad said in a statement.

Police had earlier described the shooter as a white man with a handgun.

"Without speaking," police said, "he discharged at least four rounds from the pistol and is believed to have fled on foot."

A police statement said two of the victims were in stable condition, and the third suffered "much more serious injuries." It said two are US citizens and one a legal resident.

Police confirmed that two of the young men were wearing keffiyehs, the traditional black and white Palestinian scarf.

"In this charged moment, no one can look at this incident and not suspect that it may have been a hate-motivated crime," Murad said.