Amazon.com (AMZN) is under pressure by US labor board prosecutors to agree to collective bargaining with its San Francisco warehouse workers, Bloomberg News reported Tuesday, citing court filings.

The regional director of the National Labor Relations Board alleged in a complaint filed Monday that Amazon violated federal law by refusing to bargain with San Francisco warehouse employees who signed up with the Teamsters union last year, the report said.

The complaint demands that the retailing giant recognize the Teamsters local and bargain in good faith, the report said.

Amazon and the NLRB did not immediately reply to MT Newswires' request for comment.

(Market Chatter news is derived from conversations with market professionals globally. This information is believed to be from reliable sources but may include rumor and speculation. Accuracy is not guaranteed.)