The US president's son, Eric Trump, has tweeted a video that falsely claims Democratic candidate Joe Biden used a teleprompter to help him answer questions in a television interview.
Eric Trump wrote "Unreal", above a 26-second video with the headline: 'Biden caught red-handed using a teleprompter'.
Telemundo, which broadcast the interview, said the claims were false and that it "has never allowed someone who is being interviewed on its news programmes to read answers from a teleprompter".
The network said it had set up a TV screen to allow viewers to pose questions to Mr Biden.
On screen, a woman had addressed a question to Mr Biden, after which the television apparently went blank. Mr Biden said: "I lost that lady" - not "I lost that line", as the tweet shared by Eric Trump had claimed.
President Trump has also now shared the video clip, which has currently garnered some 1.6 million views.
It's not the first time allegations have been spread online suggesting Mr Biden used a teleprompter during interview.
In mid-September, President Trump promoted rumours that his opponent was reading from a teleprompter during an interview with TV host James Corden.
The rumours were false and Mr Corden has since publicly explained that the teleprompter - seen briefly in a reflection during the show - was for his own use.
The official Donald Trump Facebook page also promoted an ad making the same claim.
Memes about Biden and teleprompters have been shared thousands of times across social media platforms. The most popular such post on Facebook in the last few days was shared nearly 60,000 times.
Of course, most politicians use a teleprompter when making speeches, and both Mr Trump and Mr Biden have been picked up in the media for their stumbles while delivering speeches.
Trevor Noah's The Daily Show posted a video in late August of Mr Trump tripping up over his words during a speech. The video was captioned: "Wasn't reading off a teleprompter supposed to be easy?".