A Molotov cocktail was thrown into the office window of an African-American congressman's office in Kansas City, Missouri, early Thursday morning, according to a statement from Congressional Black Caucus chair Marcia Fudge.
It was the second incident at the office of Rep. Emanuel Cleaver within the last six years.
No one was hurt in the incident and police are investigating.
"The Congressional Black Caucus strongly condemns this type of vandalism targeted at Congressman Cleaver, and denounces any act of violence towards Members of Congress," Fudge said in a statement. "This type of abhorrent behavior is the most ineffective means of voicing discontent or disagreement."
On Twitter, Cleaver called the incident "small" and urged backers not to "dwell" on it as the nation pauses to remember the September 11 attacks.