US President Donald Trump has signed a bill making it a federal crime to post "revenge porn" – whether it is real or generated by artificial intelligence.

The "Take It Down Act," passed with overwhelming bipartisan congressional support, criminalizes non-consensual publication of intimate images, while also mandating their removal from online platforms.

"With the rise of AI image generation, countless women have been harassed with deepfakes and other explicit images distributed against their will," Trump said at a signing ceremony on Monday in the Rose Garden of the White House.

"And today we're making it totally illegal," he said.

"Anyone who intentionally distributes explicit images without the subject's consent will face up to three years in prison."

Websites that fail to remove the images promptly, within 48 hours, will face civil liabilities.

First Lady Melania Trump endorsed the bill in early March and attended the signing ceremony in a rare public White House appearance.

The First Lady has largely been an elusive figure at the White House since her husband took the oath of office on January 20, spending only limited time in Washington.

In remarks at the signing ceremony, she described the bill as a "national victory that will help parents and families protect children from online exploitation."

"This legislation is a powerful step forward in our efforts to ensure that every American, especially young people, can feel better protected from their image or identity being abused," she said.

Some US states, including California and Florida, have laws criminalizing the publication of sexually explicit deepfakes, but critics have voiced concerns the "Take It Down Act" grants the authorities increased censorship power.

The Electronic Frontier Foundation, a nonprofit focused on free expression, has said the bill gives "the powerful a dangerous new route to manipulate platforms into removing lawful speech that they simply don't like." (AFP)