Apple Inc (AAPL.O) has restricted the use of ChatGPT and other external artificial intelligence tools for its employees as Apple develops similar technology, the Wall Street Journal reported on Thursday, citing a document and sources.

Apple is concerned about the leak of confidential data by employees who use the AI programs and has also advised its employees not to use Microsoft-owned <MSFT.O> GitHub’s Copilot, used to automate the writing of software code, the report said.

Last month, OpenAI, the creator of ChatGPT, said it had introduced an “incognito mode” for ChatGPT that does not save users’ conversation history or use it to improve its artificial intelligence.

Scrutiny has been growing over how ChatGPT and other chatbots it inspired manage hundreds of millions of users’ data, commonly used to improve, or “train,” AI.

Earlier Thursday, OpenAI introduced the ChatGPT app for Apple’s iOS in the United States.

Apple, OpenAI and Microsoft did not respond to Reuters request for comment.