More than 600 American firms including the world's largest retailer Walmart jointly wrote to Trump administration on Thursday for a prompt settlement on China-U.S. trade disputes, concerning tariffs will hurt U.S. companies and consumers.

"We remain concerned about the escalation of tit-for-tat tariffs,” the letter said, “broadly applied tariffs are not an effective tool to change China’s unfair trade practices. Tariffs are taxes paid directly by U.S. companies ... not China.”

This letter is the latest of many sent to the Trump administration by Tariffs Hurt the Heartland, the national campaign against tariffs supported by more than 150 trade groups from agriculture, manufacturing, retail and tech industries, according to Reuters.

"We urge your administration to get back to the negotiating table while working with our allies to develop global, enforceable solutions. An escalated trade war is not in the country’s best interest, and both sides will lose," the letter said.

More than 2,000 U.S. dollars will be added in costs for the average American family of four with the value of U.S. GDP to be reduced by one percent, it noted.

Possible tariffs on 300 billion U.S. dollar worth of Chinese goods, about which the public hearing will begin next week, would wipe out more than two million U.S. jobs, the letter said, quoting estimates from international consultancy the Trade Partnership.

The White House did not immediately respond to a request for comment.

Walmart, the largest U.S. private sector employer, affirmed that U.S. consumers will pay more for tariffs.

"Trade overall has been good for Americans, good for consumers ... and I realize it gets criticized at times," Walmart Chief Executive Doug McMillon said last week. He urged the Trump administration focus on how trade helps a broad number of people in the country and "not just those it harms."