BLOOMINGTON, Minn. (CBSNewYork/CBS Minnesota) -- The FBI late Saturday was investigating a bomb attack at a mosque in Bloomington, Minnesota.
Bloomington police say the explosion was reported at about 5:05 a.m. local time at the Dar Al-Farooq Islamic Center on the 8200 block of Park Avenue South, CBS Minnesota reported.
The FBI took over the investigation by early Saturday afternoon, and said in a statement that the explosion was "caused by a destructive device in violation of federal law."
The blast hit an empty office. The building sustained fire and smoke damage, but there were no injuries.
Asad Zaman, the executive director of Muslim American Sociey of Minnesota, told CBS Minnesota a device was thrown inside as people were preparing for morning prayer.
A worshiper saw someone standing by the outside window of the center's imam before the explosion, and then saw a truck speeding away from the scene before smoke starting pouring out from the window.
Worshipers extinguished the fire before first repsonders arrived.
Coverage From CBS Minnesota -- Kate Raddatz Reports:
The Muslim American Society of Minnesota and the Minnesota chapter of the Council on American-Islamic Relations are each offering a $10,000 reward for information about this crime, bringing the reward total to $20,000.
"We hope a reward will help law enforcement authorities quickly apprehend the perpetrator of this act of violence targeting an American house of worship," said CAIR-MN Civil Rights Director Amir Malik. "If a bias motive is proven, this attack would represent another in a long list of hate incidents targeting Islamic institutions nationwide in recent months."
Anyone with information is asked to call the FBI at 1-800-CALL-FBI, then select option number one.
Meanwhile, U.S. Sen. Al Franken (D-Minnesota) reacted to the explosion on Twitter Saturday afternoon.
Franken said in another tweet, "Violence like this has no place in Minnesota and no place in America."
Minnesota Gov. Mark Dayton also released a statement Saturday:
"Every place of worship, for all Minnesotans of every faith and culture, must be sacred and safe. My prayers are with the children, families, and faith leaders of the Dar Al Farooq Islamic Center today.
"I thank the Bloomington Police and Fire Departments, all other first responders, the FBI, and the ATF for their swift responses to this incident. Their investigations will be crucial in determining what happened this morning.
"I will remain in close contact with Minnesota Public Safety Commissioner Mona Dohman throughout the weekend and until this investigation is complete."
On Twitter, Rep. Erik Paulsen (R-Minnesota) said "Standing w/ Dar Al-farooq community today. Relieved to hear no one was hurt. I'm confident the investigation will get to the bottom of this."
Coverage From CBS Minnesota -- Nina Moini Reports:
In a joint press conference between the FBI, ATF and Bloomington Police Department Saturday afternoon, FBI Special Agent Rick Thornton said an "improvised explosive device" was responsible for the explosion, but wouldn't yet characterize the incident as a hate crime or act of terrorism.
"At this point our focus is to determine who and why," FBI Special Agent Rick Thornton said in a press conference. "A lot of the questions we've been receiving from the media thus far — is it a hate crime? Is it an act of terrorism? Who did it? — All these things, again, that's what the investigation is going to, is to determine who and what the motivation was."
ATF Special Agent Jim Modzelewski gave his condolences to those affected by the bombing.
"Our ultimate goal is to find the folks who are responsible for this and hopefully provide some closure to the folks that were victimized by this this morning," Modzelewski said.
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