A sensational story about the Israeli prime minister's "psychiatrist" has exploded online, but it was AI-generated, originating on one of hundreds of websites researchers warn are churning out tech-enabled fiction masquerading as news.

Propaganda-spewing websites have typically relied on armies of writers, but generative artificial intelligence tools now offer a significantly cheaper and faster way to fabricate content that is often hard to decipher from authentic information.

Hundreds of AI-powered sites mimicking news outlets have cropped up in recent months, fueling an explosion of false narratives — about everything from war to politicians — that researchers say is stoking alarm in a year of high-stake elections around the world.