MEXICO CITY - Mexico's Agriculture Minister Julio Berdegue said Sunday that the country will not "subordinate" itself to U.S. demands regarding the potential suspension of Mexican cattle imports over concerns about the screwworm pest.

Touring southeastern Mexico with President Claudia Sheinbaum, Berdegue responded to a letter from US Agriculture Secretary Brooke Rollins, who warned that without a resolution, the United States would begin restricting cattle imports from Mexico starting April 30. Rollins also requested full authorization for US contractor aircraft to conduct eradication operations.

"I have responded directly to Secretary Rollins' letter regarding the screwworm issue," Berdegue posted on social media. "We collaborate and cooperate, but we never subordinate ourselves."

READ MORE: Trump exempts three automakers from Canada, Mexico tariffs for one month

The screwworm (Cochliomyia hominivorax) is a parasitic fly species native to the Americas, whose larvae feed on the living tissue of warm-blooded animals, including humans, according to the Pan American Health Organization (PAHO).

Earlier this month, Mexican health authorities confirmed the country's first human case of myiasis caused by the screwworm, involving a 77-year-old woman in Chiapas state.

READ MORE: Mexican president presents Trump with reasons to ditch tariffs, fails to get a deal

Human myiasis tends to occur in rural populations, particularly in areas where fly populations thrive due to the presence of domestic animals, PAHO noted.