WASHINGTON (AP) — President Joe Biden called Monday for action to end the type of "hate-fueled violence" that authorities said motivated a white man to fatally shoot three Black people at a Florida store over the weekend. Biden said people must speak out about injustice.

"We can't let hate prevail, and it's on the rise. It's not diminishing," Biden said at the White House as he met with civil rights advocates and the children of the Rev. Martin Luther King Jr. on the 60th anniversary of the March on Washington.

"Silence, I believe, we've all said many times, silence is complicity," Biden said. "We're not going to remain silent and, so, we have to act against this hate-fueled violence."

Biden's meeting with the King family and other civil rights advocates came two days after Saturday's racist attack in Jacksonville, Florida. Three Black people were shot to death by a white man wearing a mask and firing a weapon emblazoned with a swastika. The shooter, who had also posted racist writings, killed himself.

Asked how he would stop hatred, Biden said: "By talking directly to the American people because I think the vast majority of the American people agree with this table," referring to the civil rights advocates who were in the room with him. "But we have to understand, this is serious."

Vice President Kamala Harris, who was at the meeting, said most people in the United States have more in common with each other than what divides them.

"Yet there are those who are intentionally trying to divide us as a nation and I believe each of us has a duty, a duty to not allow factions to sever our unity," said Harris, the first Black person elected vice president. "Our diversity is our strength and our unity is our power as a nation, and I do believe that we must be guided by knowing that we have so much more in common than what separates us."

After the meeting, King's son lamented the state of racial affairs in the U.S., saying, "we are at a very challenging and difficult time. "

"You would think America would be much further than it is," he told reporters on the White House driveway. But he said that, "when people come together, change can occur. And we must change this trajectory.."

Monday was 60 years since the March on Washington on Aug. 28, 1963, which drew tens of thousands to the nation's capital to advocate for civil rights, justice and freedom. It's where Rev. King delivered his famous "I Have a Dream" speech at the Lincoln Memorial.

The White House invited a broad group of civil rights leaders to the meeting, including Martin Luther King III, his wife, Arndrea Waters King, his sister Bernice King and the Rev. Al Sharpton, along with representatives from organizations representing Jews, Hispanics and Asian Americans, according to Sharpton's National Action Network.

Biden also addressed a reception Monday evening to mark the 60th anniversary of the Lawyers' Committee for Civil Rights Under Law, a nonpartisan, nonprofit legal organization that was established at President John F. Kennedy's request to help advocate for racial justice. Biden told the civil rights lawyers in the crowd that the country still needed them "badly" and called them "critical partners" in his administration's fight for equity.

"Today, you understand civil rights is the unfinished fight of America," he said.

In an opinion piece written for the Washington Post, Biden said the administration is working to advance King's dream of a society in which people don't judge others by their skin color.

Biden said his policies have led to a drop in Black unemployment, more small businesses being opened by Black entrepreneurs and more Black families covered by health insurance.

He's given some $7 billion to the network of historically Black colleges and universities and has emphasized appointing Black people to his Cabinet and White House staff, throughout the federal judiciary and to independent agencies like the Federal Reserve.

"For generations, Black Americans haven't always been fully included in our democracy or our economy, but by pure courage and heart, they have never given up pursuing the American Dream," Biden wrote.

He also referenced Saturday's attack in Jacksonville, Florida.

"We must refuse to live in a country where Black families going to the store or Black students going to school live in fear of being gunned down because of the color of their skin," Biden wrote.

Biden's meeting with King's family and his remarks at the reception will give the president, who is running for reelection, an opportunity to appeal to Black voters by talking about what he and the broader administration have done to help make their lives better.

But Biden has also struggled to fulfill key promises to Black voters, perhaps the most loyal group in his political base. He kept a promise to put a Black woman — the first to serve — on the Supreme Court, but has been unable to follow through on pledges to shore up voting rights or enact changes to policing to help stop violence against people of color by law enforcement. Legislation on both issues has stalled in a divided Congress.

The 1963 March on Washington is still considered one of the greatest and most consequential racial justice demonstrations in U.S. history.

The nonviolent protest attracted as many as 250,000 people to the Lincoln Memorial and provided momentum for Congress to pass landmark civil rights and voting rights legislation in the following years. King was assassinated in April 1968 in Memphis, Tennessee.

On Saturday, the same day as the shooting in Florida, thousands converged on the National Mall for a 60th anniversary commemoration.