(Reuters) -Technology giant Apple was accused by authors in a lawsuit on Friday of illegally using their copyrighted books to help train its artificial intelligence systems, part of an expanding legal fight over protections for intellectual property in the AI era.

The proposed class action, filed in the federal court in Northern California, said Apple copied protected works without consent and without credit or compensation.

"Apple has not attempted to pay these authors for their contributions to this potentially lucrative venture," according to the lawsuit, filed by authors Grady Hendrix and Jennifer Roberson.

Apple and lawyers for the plaintiffs did not immediately respond to requests for comment on Friday.

The lawsuit is the latest in a wave of cases from authors, news outlets and others accusing major technology companies of violating legal protections for their works.

Artificial intelligence startup Anthropic on Friday disclosed in a court filing in California that it agreed to pay $1.5 billion to settle a class action from a group of authors who accused the company of using their books to train its AI chatbot Claude without permission.

Anthropic did not admit any liability in the accord, which lawyers for the plaintiffs called the largest publicly reported copyright recovery in history.

In June, Microsoft was hit with a lawsuit by a group of authors who claimed the company used their books without permission to train its Megatron artificial intelligence model. Meta Platforms and Microsoft-backed OpenAI also have faced claims over the alleged misuse of copyrighted material in AI training.

The lawsuit against Apple accused the company of using a known body of pirated books to train its "OpenELM" large language models.

Hendrix, who lives in New York, and Roberson in Arizona, said their works were part of the pirated dataset, according to the lawsuit.