BRUSSELS, March 24 (Reuters) - EU antitrust chief Teresa Ribera, who has voiced concerns about Big Tech extending its dominance into artificial intelligence, will meet the CEOs of Alphabet, Meta Platforms and OpenAI on Tuesday, a European Commission agenda item shows.

The first-time meetings with Sundar Pichai, Mark Zuckerberg, and Sam Altman in San Francisco will take place as part of Ribera's week-long trip to the United States where she is scheduled to speak at an American Bar Association conference on Friday.

She will also meet Amazon CEO Andy Jassy on Wednesday.

Ribera, who has launched several investigations into Google and Meta's business practices, this month said she was examining the entire AI stack, including AI chatbots, the data used to train them and the cloud computing infrastructure.

The European Commission, which acts as the EU competition enforcer, has said risks are emerging as dominant companies favour their AI services on their own platforms to exclude rivals.

Technology giants, including OpenAI, Nvidia, Meta and Google have been investing billions on AI infrastructure to cater for booming demand.