An explosion has occurred at the Dar Al-Farooq Islamic Center near Interstate Hwy. 494 and Portland Avenue South, according to Bloomington police.

Following the incident, the FBI said the preliminary investigation indicated the explosion was caused by an “improvised explosive device”.

However, it did not characterize the device further, saying their focus was to determine the “who and why” behind the incident.

The FBI Minneapolis Field Office and the Bloomington police, ATF and other law enforcement agencies are cooperating on the investigation.

Jeff Potts, Bloomington police chief, said Saturday morning that first responders found smoke after reports of an explosion.

“There was no additional explosion or anything like that. There was no fire,” Potts said.

“It was just one explosion,” said Potts. “The first responders were able to determine there were no additional explosions, there's no additional fire and it seems as though the damage was pretty limited to one particular room.”

Mohamed Omar, the executive director of the Dar Al-Farooq Islamic Center, expressed grief over the incident.

“It was the first prayer and it's 5 a.m. The whole neighborhood was calm. People were supposed to be sleeping. That's how peaceful it should be,” said Omar.

He noted that a member of his congregation reported something suspicious right before the incident.