US House Speaker Nancy Pelosi (Reuters file photo)

US House Speaker Nancy Pelosi says she is forming a select committee to investigate the January 6 assault on the US Capitol by thousands of supporters of former President Donald Trump who were protesting against the disputed 2020 presidential election.

The committee will investigate the storming of the Capitol and will make recommendations for the prevention of any future attacks, Pelosi said on Friday.

Jan. 6 was one of the darkest days in our nation’s history, Pelosi said at a press conference, calling the violent attack a gleeful desecration of the Capitol. She said it is imperative that we establish the truth of that day, and ensure that the attack of that kind cannot happen, and that we root out the causes of it all.

She had voiced her intention to form a select committee earlier this week during a meeting with the House Democratic Steering and Policy Committee.

The Justice Department has arrested over 500 people in connection with the Capitol attack, including at least 100 people on charges of assault of a police officer, according to Attorney General Merrick Garland.

The US Capitol building on January 6 this year came under attack from the thousands of supporters of former US President Donald Trump over the disputed 2020 presidential election result.

Trump claimed that the election was rigged by the Washington establishment in favor of Joe Biden, the current president. According to recent surveys, most Republicans still believe that the election was stolen from Trump, and he is the legitimate president of the United States.

Trump’s supporters stormed the Capitol in the hope of preventing lawmakers from certifying Biden’s victory, thus overturning the outcome of the 2020 presidential election but to no avail.

Angry protesters clashed with police and tried to beat up a number of Democratic lawmakers. They also damaged some parts of the building housing both wings of Congress.

At least five people including a US Capitol police officer had died in ensuing clashes with dozens of policemen and Trump supporters getting injured.