The United States has blocked an effort by Canada and Mexico to have World Trade Organization (WTO) experts examine new U.S. labeling rules that the two neighboring countries allege are damaging meat export sales.

Both Canada and Mexico told the WTO’s dispute settlement body that U.S. country-of-origin labeling or COOL rules that require meat sold in U.S. stores to identify which country it comes from is damaging to North American trade.

“COOL is discouraging U.S. retailers, processors, feedlots and producers from buying Canadian livestock and meat. The negative impact on Canadian beef, pork and cattle exporters has been significant,” Canada said in a statement to the dispute body.

The statement noted that the United States and Canada are each other’s largest agricultural trading partner, with trade between the two countries amassing $37 billion last year.

WTO rules allow the plantiff to reject the first request for a panel in a trade dispute, but the case is likely to go forward to the next meeting of the WTO’s dispute settlement body on Nov. 19, when it cannot be rejected again.

The United States claims that the new labeling requirements are acceptable based on WTO rules.

This dispute was first raised last December and was formally submitted in May as Canadian producers said the new U.S. rules, tightened by the Obama administration, were impacting cattle and hog sales.

In a similar situation, the European Union rejected a call by the United States for a panel to review an EU ban on imports of U.S. poultry treated with antimicrobial chlorine rinses.