In the first action of its kind, the Biden administration has formally asked the Mexican government to investigate reports of “serious violations” of worker rights at a General Motors plant in central Mexico, U.S. Trade Representative Katherine Tai said. The move marks the first use of an innovative labor rights provision in the U.S.-Mexico-Canada trade agreement, which took effect last year. It also represents the first time the U.S. government has acted on its own to raise labor concerns under any trade agreement, though Washington has previously done so in response to complaints lodged by unions, said a senior administration official, who insisted on anonymity to brief reporters.