Donald Trump has stirred online outrage after posting an AI-generated video of himself promising every American access to all-healing "MedBed" hospitals, reviving a widely debunked conspiracy theory.

The deepfake video – posted on Saturday on the US president's Truth Social account – was styled as a Fox News segment and featured his daughter-in-law Lara Trump promoting the White House's launch of a "historic new healthcare system."

The phony clip then purported to show Trump announcing from the Oval Office that "every American will soon receive their own MedBed card," guaranteeing access to "new hospitals led by the top doctors" and "equipped with the most advanced technology."

The only problem? Such hospitals do not exist.

MedBed, tied to the QAnon conspiracy movement, is an imaginary medical device equipped with futuristic technology that adherents say can cure any ailment, from asthma to cancer.

Some QAnon adherents believe that "MedBed" technology was used to keep late president John F Kennedy alive for years after his assassination and was purposely being denied to ordinary citizens.

Trump later deleted the contentious post, without offering any explanation. There was no immediate comment from the White House.

But an archived version of his post and video, which offered no disclosure that it was AI-generated, widely circulated across social media platforms.

"If 'MedBed' technology were real, it would be the greatest medical advance in generations," Matthew Gertz, a senior fellow at the watchdog Media Matters, wrote on X.

"Trump should have to explain why he suggested it was using the channel he makes major policy announcements, and why he deleted it after the fact."

Fox News told US media outlet The Verge that the phony segment "never aired on Fox News Channel or any other Fox News Media platforms."

"How do you bring people back to a shared reality when those in power keep stringing them along?" asked Noelle Cook, a researcher and author of "The Conspiracists: Women, Extremism, and the Lure of Belonging."

Trump is no stranger to conspiracy theories and contentious health claims.

Last week, the president vehemently insisted that pregnant women should "tough it out" and avoid the painkiller Tylenol due to an unproven link to autism and urged major changes to the standard vaccines administered to babies.

The claim was dismissed by the World Health Organization, which asserted that neither Tylenol nor vaccines have been shown to cause autism. (AFP)