Biden appeals for unity in anti-extremism 'summit'

US President Joe Biden appealed Thursday for a united front against hate-crimes and political violence in a speech building on his bid to present himself as champion of moderate values at a time of rising extremism.

"We have to face the good, the bad and the truth. That's what great nations do and we're a great nation," Biden told a packed hall at the White House's United We Stand Summit. "You must choose to be a nation of hope, unity and optimism - or a nation of fear and division and hate."

Biden recounted, as often before, how he took the decision to challenge then president Donald Trump in the 2020 election after the Republican initially declined to condemn a 2017 neo-Nazi march in Charlottesville, Virginia.

"Charlottesville changed everything, because I believe our story is to unite as people in one nation, in one America."

But he said that a spate of racist violence - including a deadly attack on a Black church in Charleston, South Carolina, in 2015, a mass shooting targeting Latinos in El Paso, Texas, in 2019, and another gun massacre, this time targeting African Americans, in Buffalo, New York, in May - had left the country reeling.

"Many of you have lost part of your heart and soul," he told the audience, which included a cross-section of civil rights activists, religious leaders, academics and elected officials.

The White House described the day-long conference, with Biden giving the keynote speech, as a chance to highlight "the corrosive effects of hate-fueled violence on our democracy and public safety."

The summit comes just eight weeks ahead of midterm elections in which Republicans are seeking to take control of Congress.

It also comes two weeks after Biden delivered a fiery speech denouncing the "extreme ideology" of Trump, whose supporters overran the Capitol to try to overturn the 2020 election and who continues to promote far-right conspiracy theories.

A White House official told reporters that Thursday's event, which featured a panel with both Republican and Democratic mayors, was not political and would "demonstrate that we can unite across partisan lines."

However, Republicans have painted Biden as a divider for calling out Trump supporters, noting that the former president remains hugely popular with the party's voters.

Biden defended himself in his White House speech, saying he was right to speak up.

"There are those who say that when we bring this up we divide the country," he said. But "silence is complicity."

Among some of the practical measures discussed at the conference was Biden's suggestion that Congress should "get rid of special immunity for social media companies and impose much strong transparency requirements on all of them" regarding extremist content.

The provision known as Section 230 shields platforms from liability for content and has long been targeted by some in Congress.