Trump had threatened to impose tariffs in February before suspending them at the last minute, when Mexico sent 10,000 National Guard troops to their shared border to crack down on drug trafficking and illegal immigration.

Mexico will wait and see if U.S. President Donald Trump goes through with his threat to slap tariffs on its southern neighbor on Tuesday, the nation's president said on Monday, adding that Mexico has back-up plans in case the tariffs go into place.

Trump has vowed to impose 25% tariffs on all imports from Canada and Mexico, with 10% for Canadian energy. CEOs and economists say the action, covering more than $900 billion worth of annual U.S. imports from its southern and northern neighbors would deal a serious setback to the highly integrated North American economy.