Members of Congress are being urged to investigate President Donald Trump’s plan to import hundreds of thousands of metric tons of foreign beef in a bid to lower grocery store costs, amid growing frustration from farm-state lawmakers and the nation’s embattled ranchers at the proposal.

Under the plan, the administration would allow up to 300,000 metric tons of lean beef trimmings into the U.S. tariff-free from a still-unspecified source country for a 90-day period beginning September 1—which Trump said would then be sold “at 25 percent below current market prices."

“Congress needs to have an emergency hearing on this,” John Boyd, founder and president of the National Black Farmers Association, said in response to the proposal, which the president said would “reduce prices for Americans while giving space for our Great American Beef Herd to grow again.”