General Motors, the largest producer of cars in Mexico, won’t provide details on how it would react if President Trump imposes 25 percent tariffs from the two countries.

If U.S. President Donald Trump follows through on his pledge to slap 25% tariffs on imports from Mexico it could usher in a volatile new chapter in the longstanding trade relationship with the impacts hitting consumers.

For months, automakers have been taking a “wait-and-see” approach to the Trump administration’s potential tariffs.