"This is an AI-powered web browser built around ChatGPT," OpenAI chief Sam Altman said in a streamed presentation.

OpenAI has ramped up its challenge to Google, which has responded by rapidly building more AI capabilities into search and across its platform.

Altman and a team of executives demonstrated an "agent" mode that has a chatbot conduct searches on a user's behalf.

Altman said that in agent mode, ChatGPT uses the web browser independently, returning with what it finds.

"It's got all your stuff and is clicking around," Altman said.

"You can watch it or not, you don't have to, but it's using the internet for you."

Atlas will go live Tuesday on computers powered by Apple's operating system, but agent mode will only be available to users of Plus or Pro versions of ChatGPT, according to Altman.

"We want to bring this to Windows and to mobile devices as quickly as we can," Altman said, without providing a timeline.

"This is still early days for this project."

Atlas features demonstrated in the stream seemed similar to features already incorporated into Google Chrome and Microsoft Edge internet search browsers.

Tech industry rivals Amazon, Google, Meta, Microsoft and Elon Musk's xAI have been pouring billions of dollars into artificial intelligence since the blockbuster launch of the first version of ChatGPT in late 2022.

The debut of Atlas comes on the heels of Google escaping a breakup of its Chrome browser in a major US competition case, but with the judge imposing remedies whose impact remains uncertain just as AI starts to compete with search engines.

Judge Amit Mehta, who found a year ago that Google illegally maintained monopolies in online search, did not order the company to sell off its widely-used Chrome browser.

Instead, he ordered remedies including requirements to share data with other firms so they could develop their own search products, and barring exclusive deals to make Google the only search engine on a device or service.

Mehta himself noted that the landscape has changed since the US Justice Department and 11 states launched their antitrust case against Google in 2020.