Amazon.com has been accused by a U.S. labor board of illegally refusing to bargain with a union representing drivers employed by a contractor, the agency announced on Wednesday.

A federal labor board official issued a complaint against Apple Inc., accusing the iPhone maker of requiring employees to abide by overzealous non-disclosure, social media, and non-compete policies.

Amazon has said in the past that it does not have enough control over drivers' working conditions to be considered their joint employer.