Environment Secretary Theresa Villiers said the British government will “hold the line” in post-Brexit trade talks with the U.S. and refuse to allow chlorinated chicken and hormone-treated beef into the U.K.

“We will defend our national interests and our values, including our high standards of animal welfare,” Villiers said in an interview with the BBC. She said both products are banned under European Union law, and the U.K. will maintain that regulation after it leaves the bloc.

Villiers’s comments threaten to complicate any trade deal with the U.S. because President Donald Trump’s administration has been pushing the British government to ditch EU regulations entirely. U.S. hygiene rules allow chicken to be washed in chlorine to kill off bacteria that can be harmful to humans.