Police in the US Capitol responded with drawn guns and tear gas on Wednesday as swarms of protesters stormed in and sought to force Congress to undo President Donald Trump’s election loss shortly after some of Trump’s fellow Republicans launched a last-ditch effort to throw out the results, Reuters reported.

Police evacuated the House of Representatives and the Senate after pro-Trump protesters marched through the halls of Congress, forcing both chambers to suspend deliberations as they were meeting to certify President-elect Joe Biden’s victory in the November 3 election.

Reuters reported that one protester occupied the Senate dais and yelled, “Trump won that election.”

The chaotic scenes unfolded after Trump, due to leave office on January 20, addressed thousands of protesters, repeating false claims that the election was stolen from him due to widespread election fraud and irregularities.

At the time of the protest, lawmakers had been debating a last-ditch effort by pro-Trump lawmakers to challenge the results, an effort that failed to succeed.

Vice President Mike Pence, who had presided over the joint session of Congress, had already been escorted from the Senate.

Capitol Police told lawmakers in the House chamber to take gas masks from beneath their seats and prepare to put them on. Officers at the front door of the House chamber had their guns drawn as someone attempted to enter the chamber, Reuters reported.

Officers ordered people in the chamber to drop to the floor for their safety.

Election officials of both parties and independent observers have said there was no significant fraud in the November 3 contest, which Biden won by more than seven million votes in the national popular vote.