Aug 20 (Reuters) - Artificial intelligence company

Anthropic has been hit with a class-action lawsuit in California

federal court by three authors who say it misused their books

and hundreds of thousands of others to train its AI-powered

chatbot Claude.

The complaint, filed on Monday by writers and journalists

Andrea Bartz, Charles Graeber and Kirk Wallace Johnson, said

that Anthropic used pirated versions of their works and others

to teach Claude to respond to human prompts.

A spokesperson for Anthropic said on Tuesday that the

company was aware of the lawsuit and assessing the complaint but

declined to comment further, citing pending litigation. An

attorney for the authors declined to comment.

The lawsuit joins several other high-stakes complaints filed

by copyright holders including visual artists, news outlets and

record labels over the material used by tech companies to train

their generative artificial intelligence systems.

Separate groups of authors have sued OpenAI and Meta

Platforms ( META ) over the companies' alleged misuse of their

work to train the large-language models underlying their

chatbots.

The case filed Monday is the second against Anthropic

following a lawsuit brought by music publishers last year over

its alleged misuse of copyrighted song lyrics to train Claude.

The authors said in their complaint that Anthropic has

"built a multibillion-dollar business by stealing hundreds of

thousands of copyrighted books." Anthropic has drawn financial

backing from sources including Amazon ( AMZN ), Google

and former cryptocurrency billionaire Sam Bankman-Fried.

According to the complaint, the authors' works were included

in a dataset of pirated books that Anthropic used to train

Claude.

The lawsuit requested an unspecified amount of monetary

damages and an order permanently blocking Anthropic from

misusing the authors' work.