Pro-Trump supporters storm the US Capitol following a rally with President Donald Trump on January 6, 2021 in Washington, DC. Trump supporters gathered in the nation's capital to protest the ratification of President-elect Joe Biden's Electoral College victory over President Trump in the 2020 election. Photo: Samuel Corum/Getty Images/VCG

US President-elect Joe Biden condemned what he called "insurrection" at the US Capitol on Wednesday, after some supporters of the Republican incumbent, Donald Trump, broke into the building, forcing electoral vote counting to halt.

"This is not protest, it's insurrection," Biden said in Wilmington, Delaware. "This is not dissent. It's disorder. It's chaos. It borders on sedition."

The Democrat went on saying that he's calling on Trump to "go on national television now to fulfill his oath and defend the Constitution and demand an end to this siege."

Trump has refused to acknowledge defeat in the 2020 presidential race with Biden and has been pushing claims of a "fraudulent" election, which have been dismissed by US courts at different levels due to a profound lack of evidence.

In a video clip posted on Twitter in the wake of the chaotic situation, Trump urged his supporters to "go home" after demonstrations.

"You have to go home now. We have to have peace," the president said. "We have to have law and order. We have to respect our great people in law and order. We don't want anybody hurt."

The US Congress convened in a joint session earlier in the day to certify Biden's victory, but both the House and the Senate, which were separately debating an objection to the counting of Arizona's electoral votes, had to recess and evacuate after protesters breached the Capitol.

Confrontations between law enforcement officers and protesters have caused injuries from both sides. A woman who was shot on the Capitol grounds has died, according to police.

The Sergeant-at-Arms announced Wednesday evening that the US Capitol building is secure, as a citywide curfew for the District of Columbia has taken effect and will continue until Thursday morning. Meanwhile, riot police are pushing protesters away from the Capitol Hill.

House Speaker Nancy Pelosi, the congressional top Democrat, said in a letter to lawmakers that Congress will resume the counting of electoral votes Wednesday night once the Capitol is cleared for use.