President Joe Biden on Monday marked the 60th anniversary the March on Washington while issuing a stark warning about the rise of extremism in the United States in the wake of the racist shooting in Jacksonville, Florida, this weekend.

"A lot's happening around things you wouldn't think would be happening today on the anniversary of the 60 years of the March," Biden said, referencing the shooting in Jacksonville that left three Black people dead when a White gunman opened fire at a Dollar General store. The gunman left racist writings and used racial slurs before launching the attack.

Biden added, "I've said to the country we can't let hate prevail, and it's on the rise. It's not diminishing. Silence is, I believe -- and I've said many times -- silence is complicity. We're not going to remain silent."

While meeting with civil rights leaders at the White House, including family members of Dr. Martin Luther King Jr., the president cautioned against the growing trend in red states across the nation -- including Florida -- of restricting the teaching of Black history in an ongoing battle against what Republicans have called "woke" ideology in schools.

"We have to speak out, there's a whole group of extreme people trying to erase history, trying to walk away from it," Biden said. "I mean, the idea that we're sitting here -- I never thought I'd be president, let alone be president and having a discussion about why books are being banned in schools."

Earlier this year, the White House announced the Department of Education's Office of Civil Rights will appoint a new coordinator specifically tasked with combating book bans enacted at the state and local level.

In March, the American Library Association released data documenting 1,269 demands to censor library books and resources in 2022, marking the highest number of attempted book bans since the association began compiling the data more than 20 years ago.

And an April report from free speech organization PEN America found book bans rose during the first half of the 2022-23 school year. Almost a third of the bans were the result of newly enacted state laws, according to the report, which found bans were most prevalent in five states: Texas, Florida, Missouri, Utah and South Carolina.

Biden told CNN's Jeremy Diamond Monday that he has yet to speak to the families of the three victims in the Jacksonville shooting, but that he remained in contact with authorities on the ground.

"And right now, I asked whether or not it was appropriate ... to contact the families," Biden said. "Two of them are prepared to be contacted, one does not want to be contacted. I'm letting this just -- let things settle, because everyone deals with profound loss in a different way, and I know from experience, it's important to do it in a way that's most helpful and eases the anxiety most, so I haven't spoken to them yet."

Biden was joined by members of the King family, Rev. Al Sharpton, Anti-Defamation League CEO Jonathan Greenblatt, and Vice President Kamala Harris, who traveled to Florida earlier this year to lambast the state's newly approved set of standards for teaching Black history, where she warned Republican leaders in the state were trying to "replace history with lies."

"The vast majority of us have so much more in common than what separates us, 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," Harris said Monday.