Mexican President Claudia Sheinbaum says that the incoming U.S. president’s plan to institute massive tariffs on Mexican imports would bring about mutually assured economic destruction.

President Claudia Sheinbaum suggested Tuesday that Mexico could retaliate with tariffs of its own, after U.S. President-elect Donald Trump threatened to impose 25% import duties on Mexican goods if the country doesn’t stop the flow of drugs and migrants across the border.

Mexico and Canada are the United States’ top two trading partners, accounting for nearly 30% of trade volumes.