MEXICO CITY, Dec 14 (Reuters) - U.S. labor officials on Thursday asked Mexico to review whether workers at a Fujikura auto parts plant in the northern border city of Piedras Negras were being denied the right to choose their union, the U.S. Department of Labor said.

The U.S. has requested more than a dozen such probes at workplaces in Mexico under a 2020 regional trade pact that replaced NAFTA with the aim of ensuring worker protections. (Reporting by Daina Beth Solomon; Editing by Anthony Esposito)