FILE PHOTO: U.S. Trade Representative Robert Lighthizer gestures as he speaks during a meeting at the Presidential Palace, in Mexico City, Mexico December 10, 2019. REUTERS/Henry Romero

WASHINGTON (Reuters) - The USMCA trade deal does not include American “labor inspectors,” U.S. Trade Representative Robert Lighthizer said on Monday in a letter to a senior Mexican official.

On-site labor verifications would be performed by independent panelists, not by embassy attaches, Lighthizer added.

The USMCA includes language “authorizing up to five attaches from the Department of Labor to work with their Mexican counterparts, workers, and civil society groups on implementation of the Mexican labor reform,” Lighthizer wrote. “These personnel will not be ‘labor inspectors’ and will abide by all relevant Mexican laws.”

The USMCA agreement also allows for a three-person panel to investigate “good faith questions about whether workers at a particular facility are being denied key labor rights,” Lighthizer wrote. “But those verifications will be conducted by the independent panelists not by the labor attaches.”

The letter comes after Mexico suggested it could withhold authorization for labor attaches, the latest wrinkle in the dispute over the United States-Mexico-Canada trade agreement.