The White House has accused “right-wing critics” of selectively editing videos in a “misinformation” campaign to make President Joe Biden appear senile.
In the most recent incident, Mr Biden’s opponents claimed he experienced a moment of confusion that required Barack Obama to lead him off stage at a weekend fundraiser.
The White House shared other footage that they said showed Mr Biden was just pausing to take in the applause.
The mental acuity of both Mr Biden, 81, and his 78-year-old challenger, Donald Trump, have come under scrutiny as the White House race heats up.
Opinion poll after poll, however, indicates that Mr Biden’s age and faculties are drawing far more scrutiny from voters.
“It tells you everything that we need to know about how desperate Republicans are here,” press secretary Karine Jean-Pierre said at Monday’s daily press briefing.
She told reporters that “these manipulated videos [are] done in bad faith”.
The White House spokeswoman was responding to a question about a gala that Mr Biden hosted in Los Angeles on Saturday night.
The event was headlined by George Clooney, Barbra Streisand, Julia Roberts and late night TV host Jimmy Kimmel.
Conservative outlets shared a clip of Mr Biden standing on stage as the crowd applauds, before Mr Obama reaches for his arm and they walk off stage together.
The New York Post reported that Mr Biden “appeared to freeze up” at the end of the event and “had to be led off stage” by Mr Obama.
Trump shared the clip on his platform, Truth Social, commenting: “Is this really who you want to be your President?”
But allies of the president pointed to longer clips that show Mr Biden smiling and apparently taking in the crowd’s applause.
Ms Jean-Pierre said the incident showed Mr Obama and Mr Biden “have a relationship. They are friends. They’re like family to each other”.
The White House press secretary also criticised the Post’s recent framing of another Biden clip.
The newspaper last week reported that the president had “started to wander off during a skydiving demonstration” in Italy on Thursday, with other G7 leaders “needing to pull him back to focus”.
But British Prime Minister Rishi Sunak told the Telegraph the US president was simply “being very polite and went over to talk to all of [the parachute jumpers] individually”, before Italian PM Giorgia Meloni told him they would all line up for handshakes.
A clip of the interaction widely shared on X, formerly Twitter, has a community note attached, pointing out the video was cropped.
Biden allies have meanwhile been seizing on viral clips of Trump to argue that it is the Republican candidate who is lacking mental lucidity.
Mr Biden, a Democrat, is preparing to face Trump in their first televised debate of the year later this month. The White House election is in November.
