Canada’s prime minister and Mexico’s president ordered retaliatory tariffs on goods from the U.S., following through with their threats after U.S. Donald Trump sparked a trade war by imposing sweeping tariffs on imports from Canada,

The White House said the president’s order includes a mechanism to escalate the rates if the countries retaliate, as they have threatened.

Ties between the United States and Mexico have deepened over 30 years of free trade, creating both benefits and irritants.