Google was on Tuesday hit with an EU antitrust investigation over its use of online content for AI purposes, marking the latest in a series of crackdowns from the bloc on regulating U.S. big tech companies. 

The European Commission said it was investigating whether Google had breached EU competition rules by using the content of web publishers, as well as content uploaded on the online video-sharing platform YouTube, for AI purposes.

The probe will examine whether Google is distorting competition by imposing unfair terms and conditions on publishers and content creators, or by granting itself privileged access to that content and placing developers of rival AI models at a disadvantage, the Commission said. 

"AI is bringing remarkable innovation and many benefits for people and businesses across Europe, but this progress cannot come at the expense of the principles at the heart of our societies," said the bloc's commissioner for competition Teresa Ribera.

"This is why we are investigating whether Google may have imposed unfair terms and conditions on publishers and content creators, while placing rival AI models developers at a disadvantage, in breach of EU competition rules."

The Commission said it would investigate to what extent the generation of AI Overviews and AI Mode by Google is based on web publishers' content without appropriate compensation and without the possibility for publishers to refuse without losing access to Google Search.

In September, the EU fined Google nearly 3 billion euros ($3.4 billion) for breaching antitrust rules by distorting competition in the advertising technology industry.

At the time, Google's global head of regulatory affairs, Lee-Anne Mulholland said the EU decision was "wrong" and the firm would appeal. "There's nothing anticompetitive in providing services for ad buyers and sellers, and there are more alternatives to our services than ever before," she said.

The move follows a slew of actions the bloc has taken against U.S big tech companies in recent days. 

The Commission hit Elon Musk's social media app X with a 120-million-euro ($140 million) fine on Friday for breaching transparency obligations around its advertising repository and "the deceptive design of its 'blue checkmark.'"

Musk called for the European Union to be abolished in response, with key Republican officials also criticizing the decision.

Last week the EU also announced it had opened an antitrust investigation into Meta over its new policy on allowing AI providers' access to WhatsApp, which it said may breach the bloc's competition rules.

CNBC has approached Google for comment.