A fire alarm went off in a Capitol Hill building Saturday, adding to the chaos as US lawmakers worked to hash out a last-minute deal to avoid a government shutdown.

Rep. Jamaal Bowman, a Democrat from New York, is accused of pulling a fire alarm in the Cannon House Office Building, where US representatives have their offices. House Speaker Kevin McCarthy said he would seek an ethics investigation into the incident, which Bowman said was a “mistake.”

“This should not go without punishment,” McCarthy told reporters.

Bowman told reporters he had been trying to open a door. “It was a mistake. That’s all it was,” he said. “McCarthy is trying to weaponize an innocent mistake.”

The US Committee on House Administration said in a post on the social media platform X, formerly known as Twitter, an investigation into why the fire alarm was pulled is underway. The comment, attributed to Chairman Bryan Steil, a Republican representative from Wisconsin, was confirmed by the committee.

The incident was caught on camera, according to Politico. The alarm added to the already tense scene on Capitol Hill, with McCarthy working to sidestep hardliners in his own party to secure a government funding deal ahead of a midnight deadline for shutdown. The plan was tweaked to gain Democratic support, and the Senate can then take it up before — or soon after — the midnight deadline.

Read more: House Passes Bill to Avert Government Shutdown, Sends to Senate

Pulling a fire alarm is a misdemeanor in some jurisdictions. The US Capitol Police did not immediately respond to a request for comment.

--With assistance from Erik Wasson.