WASHINGTON (Reuters) - A group of U.S. Democratic lawmakers on Monday criticized Goodyear Tire & Rubber Co GT.O for refusing to let them visit its Mexican plant, and said poor conditions there raised questions about Mexican labor reforms seen as key to ensuring passage of a new U.S.-Mexico-Canada trade agreement.

FILE PHOTO: A U.S. flag flies at a Goodyear Tire facility in Somerville, Massachusetts, U.S., July 25, 2017. REUTERS/Brian Snyder

Four of the nine House of Representatives Democrats who are negotiating with President Donald Trump’s administration about the trade deal spelled out their concerns in a letter to Goodyear’s chief executive, Richard Kramer.

“We are ... disappointed that an iconic American company like Goodyear ... is failing to provide its workers in Mexico with basic labor rights that are recognized internationally and under Mexican law,” Representative Earl Blumenauer, chairman of the trade subcommittee of the House Ways and Means Committee, and three other Democrats wrote in the letter.

“While we are told that Mexico’s labor reforms and a renewed NAFTA will lead to positive change in Mexico and in America, what we saw at Goodyear clearly illustrates the entrenched way of doing business in Mexico that is based on exploiting a powerless workforce,” they said.

The Trump administration wants Congress to approve the trade deal to replace the North American Free Trade Agreement (NAFTA), but House Democrats have said they will not proceed until their labor, climate, enforcement and pharmaceutical concerns are met.

Goodyear said it had received the letter and would respond.

“We strongly disagree with the statements made about our working conditions and labor practices, and expect to provide a comprehensive response to the letter within the allotted timeframe,” spokeswoman Melissa Monaco said in a statement early on Tuesday.

The company on Friday said the need to train and certify workers, and pressure to achieve full production capacity by the end of year, meant it was able to host only “limited outside visits.” It said it had offered the delegation to explore an offsite meeting with executives but received no response.

Blumenauer led a bipartisan congressional visit to Mexico from July 18-22. Democratic Representatives Rosa DeLauro, Terri Sewell and Jimmy Gomez were also on the trip and signed the letter.

They said they met with workers who were fired from the Goodyear plant, but were not permitted to visit the plant.

They asked the company to respond within two weeks to reports of “poor working conditions, inadequate wages, illegal termination and discrimination” at the facility, and to say how much of the output from the plant was sent to the United States.

Goodyear’s San Luis Potosi plant opened in 2017, with wages ranging from $2 to $6 an hour, while most of Goodyear’s U.S. workers receive a base rate of $23 per hour, the lawmakers said.

A wildcat strike at the Mexican plant in April 2018 included 600 of the 800 workers, the lawmakers said, adding that 57 of those who participated were later systematically fired.