Updated

Authorities are investigating an explosion at a mosque in suburban Minneapolis Saturday that damaged the imam's office as congregants were preparing for morning prayers.

The blast happened at around 5 a.m. at the Dar Al-Farooq Islamic Center in Bloomington. No injuries were reported. 

Mohamed Omar, the center's executive director, told Fox 9 the congregation saw smoke billowing out of a broken window leading to the imam's office and called police.

"I was sad, and I was surprised," Omar told the station. "I was shocked. It was first prayer, it was 5 a.m. and the whole neighborhood was calm, people were supposed to be sleeping. That's how peaceful it should be."

Asad Zaman, director of the Muslim American Society of Minnesota, said at a news conference that a witness saw something being thrown at the imam's office window from a "van or truck" before the blast. Omar said a worshipper saw a pickup truck speeding away afterward.

There were 15 to 20 people inside the mosque when the blast happened. Worshippers managed to extinguish the blaze before firefighters arrived, the society said in a news release.

Omar said the mosque, which primarily serves people from the area's large Somali community, has received threatening phone calls and emails in the past.

The mosque serves as a religious center and community organizing platform for Muslim activists and leaders in the area, said the society, which is offering a $10,000 reward for information that leads to an arrest or conviction.

Trevin Miller, who lives across the street, told the Star Tribune that the explosion woke him up, saying that he felt it on his "insides."

Yasir Abdalrahman, a worshipper at the mosque, said the explosion was "unimaginable."

"We came to this country for the same reason everyone else came here: freedom to worship," Abdalrahman said. "And that freedom is under threat. Every other American should be insulted by this."

The FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives are involved in the investigation.

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