The US Capitol is on lockdown amid a tense situation with demonstrators outside the building, according to Capitol police officers, as President Donald Trump’s supporters attempt to break into the building while lawmakers count the Electoral College votes certifying President-elect Joe Biden’s win.

Hundreds of pro-Trump protesters have gathered on the House side of the Capitol building. CNN personnel inside the House building report hearing fireworks and chants of “USA! USA!”

The protesters have breached exterior security barriers, and video footage shows protesters gathering and some clashing with police near the Capitol building.

Shortly after 1 p.m. pro-Trump protesters pushed through barriers set up along the perimeter of the Capitol, where they tussled with officers in full riot gear, some calling officers “traitors” for doing their jobs.

Protesters could be seen pushing against metal fences and police using the fences to push protesters back, while other officers reached over the top to club people trying to cross their lines.

Flash bangs could be heard near the steps of the Capitol as smoke filled the air. In some instances officers could be seen deploying pepper spray. Tear gas has been deployed, but it’s not clear whether by protesters or police, and people wiped tears from their eyes while coughing.

Trump supporters chanted “USA” and waved American and “Don’t Tread on Me” flags toward the front of the crowd after things had calmed some.