“They have been aggressively recruiting Tesla engineers with massive compensation offers and have unfortunately been successful in a few cases,” Musk said of OpenAI’s hiring efforts in an X post on Wednesday.

Musk made the remarks in response to a story by The Information that was published on the same day. According to the report, Tesla machine-learning scientist Ethan Knight is moving over to join Musk’s AI company, xAI.

“Ethan was going to join OpenAI, so it was either xAI or them,” Musk wrote on X.

Representatives for OpenAI did not immediately respond to a request for comment from Business Insider sent outside regular business hours.

Competition for AI talent has been heating up as tech companies race to become dominant players in the field. Aside from offering eye-watering salaries, some Big Tech leaders have adopted a personal touch when it comes to wooing engineers.

Meta’s Mark Zuckerberg has been reportedly writing personal emails to AI researchers at Google’s DeepMind, per The Information. In fact, Zuckerberg’s Meta has even offered jobs to candidates without conducting any interviews, the outlet reported.

It’s not just Zuckerberg’s who’s had to do personal reachouts. Google cofounder Sergey Brin had to personally call an employee who was thinking of leaving Google for OpenAI. According to The Information’s report, Brin made several promises to convince the employee to stay, including an offer of higher pay.

“The talent war for AI is the craziest talent war I’ve ever seen!” Musk said on Wednesday.