Investing.com -- Apple filed a lawsuit on Friday against OpenAI and two former Apple employees, accusing them of stealing the company’s trade secrets.

The complaint was filed in the U.S. District Court for the Northern District of California. Apple named Chang Liu and Tang Yew Tan, both former employees who joined OpenAI, as defendants in the case.

According to the court filing, Apple alleges that Tang Yew Tan, now serving as OpenAI’s chief hardware officer, is using Apple trade secrets in his current role. The lawsuit claims that Chang Liu stole dozens of confidential hardware files after joining OpenAI.

Apple also accuses OpenAI of instructing job candidates to bring Apple prototypes and design artifacts to interviews. The iPhone maker alleges that OpenAI asked suppliers highly specific questions about Apple’s manufacturing processes and components that only insiders would know to ask.

The lawsuit further claims that OpenAI persuaded an Apple partner to perform the company’s metal-finishing techniques for OpenAI’s hardware development, despite contract limits that would prohibit such actions.

The legal action marks a sharp escalation in tensions between Apple and the ChatGPT maker that have been building for several months.