WASHINGTON — Warning that "this venom and violence cannot be the story of our time," President Joe Biden convened an array of civil, government and faith leaders at the White House on Thursday, hoping to ignite a society-wide effort to tamp down on violence sparked by hate.

Biden's keynote at the White House's United We Stand summit was aimed at combating the kind of hate-fueled violence that has scarred communities including El Paso, Buffalo and Orlando in recent years, and that the president warned can also stem from political divisiveness.

"There are core values that should bring us together as Americans," Biden told a crowd gathered in the East Room. "One of them is standing together against hate, racism, bigotry and violence that has long plagued our nation."

Biden said the themes of Thursday's event are at the center of his presidency. He has long said that the deadly Unite the Right rally in Charlottesville in 2017 - and President Donald Trump's comments about there being "very fine people on both sides" - was "a wake-up call for us as a country" and inspired him to launch a third bid for the presidency. He has also blasted Republicans who participated in or condoned the Capitol riot as "MAGA Republicans" whose beliefs are dangerous and antithetical to American values.

"Unfortunately, such hateful violence and threats are not new to America," he said. "There's a through line of hate, from massacres of Indigenous people and the original sin of slavery, the terror of the [Ku Klux Klan] and then anti-immigration policies against the Irish, Italians, Chinese, Mexicans - so much of it is laced through our history."

Still, as the midterm elections approach and Biden has sought to draw a line of demarcation between Democrats and Republicans, he has been accused of contributing to the divisiveness. At a speech in Philadelphia, Biden labeled some members of the opposition party "MAGA Republicans" reminiscent of fascists.

"Too much of what's happening in our country today is not normal," he said in the prime-time speech on the "battle for the soul of the nation." "Donald Trump and the MAGA Republicans represent an extremism that threatens the very foundations of our Republic."

House Minority Leader Kevin McCarthy (R-Calif.) said at the time that Biden was "slandering tens of millions of Americans as fascists." And many Republican leaders have questioned how Biden can claim to unite the country by branding a large group of Americans as a threat to democracy.

Other critics have said that while the president routinely mentions the need to stand against hate-fueled violence, he has put forth few cogent actions to quell it.

"States need support from the federal government to respond to white nationalism and political violence, including clear condemnation of the anti-Semitic 'great replacement' conspiracy theory and policies that tackle this threat head-on," the Western States Center, a nonprofit that works to promote progressive policy change, wrote in an open letter to the administration in advance of the summit.

Thursday's day-long event featured survivors of hate-centered violence, mayors and other civic leaders, members of the clergy, and a former member of a hate group. Before his keynote, Biden was introduced by Susan Bro, the mother of Heather Heyer, who was killed by a man who plowed his vehicle into a crowd of counterprotesters during the White supremacist rally in Charlottesville.

"Her murder resonated around the world, but the hate did not begin nor end there," Bro said. "White supremacist organizers have worked for months here to create a culture of hate and dissidence with numerous rallies, marches and visits in Charlottesville." One of the rallies, Bro said, happened just months after Heyer was killed.

In conjunction with Thursday's event, the White House announced new initiatives and collaborations that it says will allow cultural institutions, schools and law enforcement agencies to better combat hate-fueled violence. Biden also called on Congress to pass part of his budget proposal that would increase funding to protect houses of worship from violence. And he said Congress should hold social media companies accountable for allowing hate speech to spread unchecked on their platforms.

Eric Ward, senior adviser at the Western States Center, said the summit was a good first step, but he emphasized that the fight to stem hate crimes has been going on in some American communities for years. The infusion of presidential support was helpful, but cities and towns need additional resources to make progress.

"We should all understand that local communities are already out there. Local governments are already out there around the country, attempting to build responses. What they need is support," Ward told The Washington Post. "If Portland, Oregon, had received that type of assistance or coordination in 2017, in these early days, I don't think that we'd be telling the stories about Portland, Oregon, that we are telling today."

Biden characterized Thursday's effort as a first step and said the White House should also invest in programs that help communities inoculate themselves against such violence, including "training election officials who really have become a target of political violence," particularly volunteers from minority groups who "appear to be on the receiving end of more aggressive intimidation."

He said the federal government should also invest in criminal justice information-sharing against perpetrators of hate crimes, who often travel across city and state lines to commit crimes.

When questioned at Thursday's White House news briefing, press secretary Karine Jean-Pierre said the summit was not a panacea.

"Clearly, we believe these deliverables, this rundown of actions that I've provided, is a first step to getting us to a place where we're dealing with real issues, where we're addressing hate-fueled violence in these communities that we see."

She also defended Biden's words about "MAGA Republicans," saying the president's statements reflect the opinions of the bulk of Americans who oppose political violence.

"The president is hosting this event to highlight that the vast majority of Americans, despite our myriad differences, are united in opposition to hate-fueled violence," she said. "This is a core American value that is shared by people of all faiths."

In the Philadelphia speech, and in statements afterward, Biden sought to differentiate between mainstream Republicans and those who embrace extreme ideologies. "Not every Republican - not even a majority of Republicans - are MAGA Republicans. Not every Republican embraces their extreme ideology."

The Biden Justice Department has boosted federal hate-crime prosecutions under Attorney General Merrick Garland, filing 20 cases in the first half of this year, a pace that eclipses any single year of the Obama or Trump administrations. Although Biden has emphasized that he would not seek to influence the Justice Department, officials have held the prosecutions up as a way to show that his administration is addressing hate crimes.

Bro said much more needs to be done, especially because the voices of divisiveness are still active, even in the place where her daughter was killed.

"To this day, white supremacist stickers are often placed at the site of the murder and on the University of Virginia campus along with recruitment fliers," Bro said.

"We're here to share our experiences and our strategies to combat hate," she said. "But it must continue beyond today. Governments, corporations, communities and organizations must continue to move forward in ways that pull us all together. We must shine the light of truth, justice and equity on this issue, and reject those who want us to live in fear of our fellow man."

The Washington Post's David Nakamura contributed to this report.