WASHINGTON (AP) — President Joe Biden celebrated the Juneteenth holiday early with a Monday concert on the White House South Lawn with singers including Gladys Knight and Patti LaBelle.

"Black history is American history," Biden told the crowd.

The Democratic president warned that some "old ghosts" in new clothes — a veiled reference to some of his Republican rivals — seek to take away their freedoms by making it harder for Black Americans to vote.

This year's concert came as the presidential election is intensifying, with Black voters sure to play an important role. Biden won 91% of Black voters in 2020, according to AP VoteCast.

Presumptive Republican nominee Donald Trump, the former president, contends that more Black voters are turning his way. While Black Americans have consistently voted Democratic, minor changes in political loyalties or low turnout in key states could influence who wins in November.

The Juneteenth concert had blatant political overtones with emcee Roy Wood Jr., the comedian and actor, ticking through policy achievements by the Biden administration such as capping insulin prices and forgiving student debt.

Biden signed a law in 2021 that made June 19, or Juneteenth, a federal holiday. It commemorates the day in 1865 when the last enslaved people in the United States learned they were free, more than two years after then-President Abraham Lincoln signed the Emancipation Proclamation that liberated slaves in the Confederacy during the Civil War.

Generations of Black Americans have celebrated Juneteenth, which marks the enforcement of the proclamation in Texas with the Civil War ending in a Union victory.

Others at the White House event included singer and songwriter Raheem DeVaughn, gospel singer Kirk Franklin, rapper Doug E. Fresh, singer and songwriter Anthony Hamilton, singer and actress Patina Miller, country singer and songwriter Brittney Spencer, jazz musician Trombone Shorty and singer and songwriter Charlie Wilson.

There was a festive mood, with Vice President Kamala Harris dancing on stage with Franklin.

Harris, speaking at the concert, said this year's Juneteenth will be a national day of action on voting, an effort to promote participation in the election and oppose efforts at voter suppression.