Anger over a Somali-born teenager's failed plan to blow up a van full of explosives during a US Christmas tree lighting ceremony erupted when a fire damaged an Islamic centre frequented by the suspect.
Police don't know who started the blaze or exactly why, but they believe the Islamic centre in Corvallis , Portland, Oregon, was targeted because terror suspect Mohamed Osman Mohamud, 19, worshipped there.
Yosof Wanly, the imam at the Salman Alfarisi Islamic Centre, said he was advised by friends to take his family out of their home because of the potential threat of hate crime.
No one was injured, and the fire was contained to one room.
"We know how it is, we know some people due to ignorance are going to perceive of these things and hold most Muslims accountable," Wanly said. "We do what we can, but it's a tough situation."
The failed attack on Portland's Christmas tree lighting ceremony on Friday is testing tolerance in what has typically been a state accepting of Muslims, and the FBI warned it would not accept retribution for Mohamud's alleged plot.
The agency was working closely with leadership at the centre as agents investigated the fire, said Arthur Balizan, Special Agent in Charge of the FBI in Oregon. A 10,000 dollar (£6,400) reward was offered for information leading to an arrest.
Ahson Saeed, 25, who worships at the centre, called the fire "a heinous act."
Mohamud was being held on charges of plotting to carry out a terror attack in Portland. He is scheduled to appear in court on Monday.
On Friday, he parked what he thought was a bomb-laden van near the ceremony and then went to a nearby train station, where he dialled a mobile phone that he believed would detonate the vehicle, federal authorities said. Instead, federal authorities moved in and arrested him. No one was hurt.