The newspapers, which include The New York Daily News and The Chicago Tribune, are owned by Alden Global Capital, a Florida-based hedge fund that created the second-largest US newspaper group behind USA Today owner Gannett when it bought the Tribune publishing chain in 2021.

"This lawsuit arises from defendants purloining millions of the publishers' copyrighted articles without permission and without payment to fuel the commercialization of their generative artificial intelligence products, including ChatGPT and (Microsoft's) Copilot," according to the filing.

"As this lawsuit will demonstrate, defendants must both obtain the publishers' consent to use their content and pay fair value for such use," the filing said.

OpenAI and its Microsoft backer were also accused of offering up verbatim excerpts of full articles as well as attributing misleading or inaccurate reporting to the publications in certain requests.

Other newspapers involved in the suit were The Orlando Sentinel, The Sun Sentinel of Florida, The San Jose Mercury News, The Denver Post, The Orange County Register and The St. Paul Pioneer Press.

In a statement, OpenAI did not refer to the accusations specifically but said "we take great care in our products and design process to support news organizations."

OpenAI pointed to the "constructive partnerships and conversations with many news organizations around the world to explore opportunities, discuss any concerns, and provide solutions."

This referred to the news outlets that have entered partnerships with the Microsoft-backed startup instead of going to court.

They include The Associated Press, Financial Times, Germany's Axel Springer, French daily Le Monde and Spanish conglomerate Prisa Media.

The suit on Tuesday closely resembles a case filed by The New York Times in December, in which OpenAI is also accused of stealing content to train its powerful AI.

In that case, OpenAI strongly pushed back, arguing the use of publicly available data including news articles for general training purposes is fair use.

OpenAI also accused the Times of violating ChatGPT's user guidelines to generate the content that suited its case.

Microsoft declined to comment on the suit.