WASHINGTON (AP) — Protesters backing President Donald Trump breached the U.S. Capitol on Wednesday in violent clashes with police that force a delay in the constitutional process to affirm Joe Biden’s victory in the November election.

Trump had urged his supporters to come to Washington to protest Congress’ formal approval of Biden’s win. Several Republican lawmakers have backed his calls, despite there being no evidence of fraud or wrongdoing in the election.

Both chambers abruptly recessed as dozens of people breached security perimeters at the Capitol and lawmakers inside the House chamber were told to put on gas masks as tear gas was fired in the Rotunda.

A chaplain prayed as police guarded the doors to the chamber and lawmakers tried to gather information about what was happening.

An announcement was played inside the Capitol as lawmakers were meeting and expected to vote to affirm Biden’s victory. Due to an “external security threat,” no one could enter or exit the Capitol complex, the recording said.

Both chambers abruptly went into recess. The District of Columbia’s Mayor, Muriel Bowser, issued a curfew for 6 p.m.

The skirmishes occurred outside in the very spot where president-elect Biden will be inaugurated in just two weeks.

Protesters tore down metal barricades at the bottom of the Capitol’s steps and were met by officers in riot gear. Some tried to push past the officers who held shields and officers could be seen firing pepper spray into the crowd to keep them back. Some in the crowd were shouting “traitors” as officers tried to keep them back.

A suspicious package was also reported in the area, Capitol Police said.

The skirmishes came just shortly after Trump addressed thousands of his supporters, riling up the crowd with his baseless claims of election fraud at a rally near the White House on Wednesday ahead of Congress’ vote.

“We will not let them silence your voices,” Trump told the protesters, who had lined up before sunrise to get a prime position to hear the president.