Aug 2 (Reuters) - A U.S. labor board official recommended setting aside the results of a landmark Amazon.com Inc union election in Alabama, where employees had voted against making their warehouse the online retailer's first to organize in the United States, according to a press release from the Retail, Wholesale and Department Store Union.

The U.S. National Labor Relations Board and Amazon did not immediately respond to requests for comment. (Reporting by Jeffrey Dastin in San Francisco; Editing by Lisa Shumaker)