The United States will impose tariffs on steel and aluminum imported from Canada, Mexico, and the European Union, according to the Associated Press.

An ad valorem rate of duty of 25 percent will be levied on affected steel imports and 10 percent on affected aluminum imports.

President Donald Trump originally announced the protectionist tariffs in March, saying that the measures were necessary to protect US national security.

“This relief will help our domestic steel industry to revive idled facilities, open closed mills, preserve necessary skills by hiring new steel workers, and maintain or increase production, which will reduce our Nation’s need to rely on foreign producers for steel and ensure that domestic producers can continue to supply all the steel necessary for critical industries and national defense,” President Trump said in his proclamation announcing the steel tariffs.

The administration specifically excluded Canada and Mexico from the steel and aluminum tariffs saying that the US’s neighbors “present a special case.”

“Given our shared commitment to supporting each other in addressing national security concerns, our shared commitment to addressing global excess capacity for producing aluminum, the physical proximity of our respective industrial bases, the robust economic integration between our countries, the export of aluminum produced in the United States to Canada and Mexico, and the close relation of the economic welfare of the United States to our national security, see 19 U.S.C. 1862(d), I have determined that the necessary and appropriate means to address the threat to the national security posed by imports of aluminum articles from Canada and Mexico is to continue ongoing discussions with these countries and to exempt aluminum articles imports from these countries from the tariff, at least at this time,” President Trump said in his proclamation announcing the aluminum tariffs.

However, it appears that the slow pace of the trilateral North American Free Trade Agreement renegotiations weighed on the administration’s decision.

US Commerce Secretary Wilbur Ross said that the NAFTA talks were “taking longer than we had hoped.”

Last year, US imports affected by the tariffs from Canada totaled US$7.2 billion in aluminum and US$2.4 billion in steel, and US$0.5 billion in aluminum and US$1.5 billion in steel from Mexico.

It is unclear if the Trump administration plans to place tariffs on aluminum and steel imports from other US allies.

In a revised proclamation on March 22, President Trump excluded a number of countries from the original tariffs, including Australia, Argentina, Brazil, the EU, and South Korea.

President Trump said in the proclamation that the US “has an important security relationship” with both Argentina and Brazil, including in Latin American security concerns, reciprocal investment in industry, and “strong economic integration.”