If sustained, U.S. tariffs imposed on Mexico and Canada will have a significant adverse impact on those countries, the International Monetary Fund said on Thursday, citing the strong integration of both countries with the U.

The IMF warned Canada and Mexico are vulnerable to “significant adverse economic impact” if President Donald Trump sustains tariffs on those countries given their exposure to US markets.

IMF spokesperson Julie Kozack said the U.S. tariffs on Mexico and Canada and new duties on China, along with responses from China and Canada, and potentially Mexico, amounted to significant new developments. She said the IMF would release a more comprehensive assessment at the spring meetings of the IMF and World Bank in Washington in April.