MILAN — Italy’s data protection authority on Thursday blocked access to the Chinese AI application DeepSeek to protect users’ data and announced an investigation into the companies behind the chatbot.

The authority, called Garante, expressed dissatisfaction with DeepSeek’s response to its initial query about what personal data is collected, where it is stored and how users are notified.

“Contrary to the authority’s findings, the companies declared that they do not operate in Italy, and that European legislation does not apply to them,” the statement said, noting that the app had been downloaded by millions of people around the globe in just a few days.

DeepSeek’s new chatbot has raised the stakes in the AI technology race, rattling markets and catching up with American generative AI leaders at a fraction of the cost.