Supporters of President Donald Trump rioted at the U.S. Capitol on Wednesday as Congress convened to certify the Electoral College votes, which are expected to confirm Joe Biden as the next president of the United States.

Protesters clashed with police and U.S. Senate proceedings were halted with lawmakers being escorted from the chamber. Protestors freely roamed through the Capitol complex, including the Senate chamber, where one man stood on the president of the Senate’s chair and shouted, “Trump won that election!” Vice President Mike Pence, who had been presiding over the count of Electoral College votes, was ushered out of the Senate as the U.S. Capitol Complex went into lockdown as Trump supporters began breaching the complex.

Several law enforcement officials said at least one person in the Capitol building had been shot.