KANSAS CITY, Mo. -- Police say someone threw a Molotov cocktail through a window at U.S. Rep. Emanuel Cleaver's Kansas City district office, reports CBS affiliate KCTV.

Rep. Emanuel Cleaver

A security alarm alerted police shortly before 3 a.m. Thursday to a smashed window at the building.

On the ground below the window, police found two broken bottles with paper towels sticking out the necks of the bottles. There was also a chemical odor reminiscent of lighter fluid, police said.

Investigators say the homemade explosive did not blow up, and no one was injured, which Cleaver confirmed in a tweet Thursday.

Folks, my staff is safe and law enforcement is investigating. Focus today should be on greater things. — Rep. Emanuel Cleaver (@repcleaver) September 11, 2014

Agents from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives are investigating.

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This is the second incident within the last six years when in which items were thrown at the building, said John Jones, Cleaver's chief of staff.

Jones said none of the staff was in the building and Cleaver was in Wash., D C.

"We have been in constant contact with the staff, and we thank the Kansas City police, as well as the Kansas City Bomb and Arson Squad for their quick response and thorough work," Jones said.

Congressional Black Caucus Chair Marcia L. Fudge of Ohio released a statement condemning the attempted arson attack.

"This type of abhorrent behavior is the most ineffective means of voicing discontent or disagreement," Fudge said in the statement.