US House Speaker Nancy Pelosi's office damaged during Capitol attack

Pro-Trump rioters -- who overtook the US Capitol on Wednesday and stormed past police barricades -- vandalised the office of Nancy Pelosi, Speaker of the House of Representatives.

Pelosi's aides said the mob shattered a big mirror in the office of the 80-year-old top Democrat and took the nameplate from above the door of her office in the highly-secure building.

One image captured a Trump supporter sitting with his feet up on the desk of Pelosi, a fierce critic of the President Donald Trump, a Republican.

Rioters flipped over tables and tore down photographs from the walls, according to The New York Times.

CNN reported earlier that a photo from inside her office suite showed a folder with the words "we will not back down" written on it.

The folder was found after rioters stormed the US Capitol as members of Congress were meeting to certify President-elect Joe Biden's Electoral College win.

The veteran politician from California was re-elected Speaker on January 3. Pelosi has led her party in the House of Representatives since 2003 and is the only woman to be speaker.

Pelosi struck a defiant tone returning to the House chamber on Wednesday night, saying rioters had failed in their mission and assuring they would face justice.

"To those who strove to tear us from our responsibility, you have failed," she said. "To those who engaged in the gleeful desecration of this, our temple of ... American democracy, justice will be done."

She then assured Americans that the House would continue to be about the people's business, starting tonight with certifying the election of President-elect Joe Biden.

"Despite the shameful actions of today, we still will do so," said Pelosi. "We will be part of a history that shows the world what America is made of."

"Congress has returned to the Capitol," she said. "We always knew that this responsibility would take us into the night. We will stay as long as it takes," Pelosi was quoted as saying by CNN.

Earlier, Pelosi joined Senate Democratic Leader Charles Schumer in calling on Trump to demand protesters to leave the Capitol.