President Joe Biden sparked health concerns after he appeared to freeze on stage.
The 81-year-old President froze for about a minute before his speech became slurred during a Juneteenth celebration at the White House.
Biden appeared to pause while Vice President Kamala Harris and Second Gentleman Doug Emhoff, danced along to the band.
It was only when Philonise Floyd, brother of the late George Floyd, eventually noticed the pause and placed his arm around him in an apparent effort to help.
The evening was hosted by the actor Roy Wood Jr., who heaped praise upon Biden and Harris for their work with the black community. He gave brief African American history lessons between musical offerings over the course of the event.
When Biden took to the podium he suffered another deeply off-putting moment, when his speech became slurred beyond comprehension.
During a part of the address, Biden said: "The day reminds us that we have a helluva lot more work to do. Let's keep marching. Let's keep the faith."
Harris also took a turn at the podium, identifying this year's Juneteenth holiday as a day of action for voting rights ahead of the all-important November election.
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The White House welcomed a number of performers ahead of the holiday, including Gladys Knight, Patti LaBelle, rapper Doug E. Fresh and gospel singer Kirk Franklin.
In 2021, Biden signed a law making June 19 a federal holiday commemorating the day in 1865 when the last of the American slaves learned they had been emancipated.
In recent polls, Biden has been struggling to match the historic support Democratic presidential candidates have won from black voters, numbers he will need in order to have a shot at a second term when he goes head-to-head against Donald Trump in November.
In a speech, Biden warned the black community, 90 percent of whom voted for him in 2020, that "old ghosts" in new outfits - his Republican competitors - were afoot, working to seize their freedoms and restrict their voting access.
It comes as the Biden administration will lift its ban on allowing a controversial Ukrainian military unit to use US weapons.
The State Department reversed a decade-old prohibition on the Azov Brigade from using American training and weapons after a new analysis found no evidence of human rights violations by the unit.