(Reuters) -The New York Times has sent Perplexity a "cease and desist" notice demanding the company stop using the newspaper's content for generative AI purposes, the startup said on Tuesday, marking the latest clash between the news publisher and an AI firm.

The news publisher said in the letter, a copy of which it shared with Reuters, that the way Perplexity was using its content, including to create summaries and other types of output, violates copyright law. NYT declined to provide additional comment on the matter.

Since the introduction of ChatGPT, publishers have been raising the alarm on chatbots that can comb the internet to find information and create paragraph summaries for the user.

In the letter to Perplexity dated Oct. 2, NYT demanded the AI firm "immediately cease and desist all current and future unauthorized access and use of The Times's content."

It also asked Perplexity to provide information on how it is accessing the publisher's website despite its prevention efforts.

Perplexity had previously assured publishers it would stop using "crawling" technology, according to the letter. Despite this, NYT said its content still appears in Perplexity.

"We are not scraping data for building foundation models, but rather indexing web pages and surfacing factual content as citations to inform responses when a user asks a question," Perplexity told Reuters.

The startup also said it plans to respond by an Oct. 30 deadline set by NYT to provide the requested information.

NYT is also tussling with OpenAI, which it had sued late last year, accusing the firm of using millions of its newspaper articles without permission to train its AI chatbot.

Earlier this year, Reuters reported multiple AI companies were bypassing a web standard used by publishers to block the scraping of their data used in generative AI systems.

Perplexity faced accusations from media organizations such as Forbes and Wired for plagiarizing their content, but has since launched a revenue-sharing program to address some concerns put forward by publishers.