A Southern California mosque was damaged by fire on Friday, and its leader said people there at the time believe it was intentionally set.

Flames were reported just after noon at the Islamic Center of Palm Springs, according to the Riverside County Fire Department. The fire was contained to the small building's front lobby, and no one was injured. Its cause is under investigation.

People there described hearing a "loud boom" and seeing flames, said Reymundo Nour, the mosque's acting imam, who was not on the site at the time. He said the mosque had been "fire-bombed."

The FBI was assisting local law enforcement in determining the cause, agency spokeswoman Laura Eimiller said.

The mosque is about 75 miles from San Bernardino, where last week a couple who federal officials say were inspired by Islamist extremists killed 14 people. Some Muslims in Southern California and beyond have worried about the potential for reprisals, while leaders of various faiths have called for tolerance.

The mosque was hit by gunfire in November 2014 in what authorities investigated as a possible hate crime. No one was injured in the early morning incident.