US President Donald Trump said on Monday that Washington would apply previously delayed tariffs against Mexico and Canada.
The 25% tariffs came into effect at 0501 UTC on Tuesday as planned, after the two sides failed to present a deal. Trump had ordered a 30-day delay on the tariffs early last month.
Trump indicated he was not willing to give the two North American countries an extension of the delay.
Energy resources from Canada are to have a lower 105 levy under the tariff regime.
Trump also said that reciprocal tariffs against countries imposing duties on US products would come into effect on April 2.
Besides the levies on ths US' two neighbors, Trump also imposed 10% tariffs on Chinese goods in February. The rate is set to rise to 20% on Tuesday.
Trump has said he also plans to impose 25% tariffs on goods from the European Union.
Canada to impose 25% retaliatory duties on US imports
Canada is expected to impose a 25% tariff on imports from the United States in retaliation to US tariffs.
On Monday, Canadian Prime Minister Justin Trudeau said that if the US tariffs go into effect, Canada will impose matching 25% tariffs on up to $155 billion (€148 billion) in US imports.
"Canada will not let this unjustified decision go unanswered," Trudeau said in a statement.
"Our tariffs will remain in place until the US trade action is withdrawn, and should US tariffs not cease, we are in active and ongoing discussions with provinces and territories to pursue several non-tariff measures," he said, urging the US administration to reconsider its tariffs.
China to impose fresh tariffs on US farm imports
China announced it will impose additional tariffs of up to 15% on imports of key US agricultural products, including chicken, pork, soybeans and beef.
The tariffs, announced by the Ministry of Commerce, will take effect on March 10. The move follows US President Donald Trump's order to double tariffs on imports of Chinese goods to 20% across the board.
Imports of US-grown chicken, wheat, corn and cotton will face an additional 15% tariff, the ministry said. Meanwhile, tariffs on sorghum, soybeans, pork, beef, seafood, fruits, vegetables and dairy products will increase by 10%.
Also on Tuesday, Beijing placed 10 more US companies on its list of unreliable entities, which would bar them from engaging in China-related import or export activities and from making new investments in the country.
The companies include defense contractors such as Lockheed Martin Missiles and Fire Control, Lockheed Martin Aeronautics and Lockheed Martin Missile System Integration Lab.
How have the markets reacted?
Late Monday, US stocks closed sharply lower after Trump confirmed the tariffs were coming into effect.
The Dow Jones Industrial Average slipped 1.5%, the broad-based S&P slid 1.8% and the tech-rich Nasdaq closed down 2.6%.
On the world's financial markets, stocks also fell. Japan's Nikkei dropped 1.84% and Taiwan's benchmark went down 0.5%.
Hong Kong's Hang Seng index fell 1.3%, while blue chips on the mainland slipped 0.2%.
Europe also seemed headed for a downturn, with STOXX 50 futures pointing down 0.8%. The euro was steady at $1.0484 after going up 1.1% on Monday. Sterling was steady at $1.2697 after a 1% rise. Euro zone bond yields also fell in early trading on Tuesday.
China urges US to return to dialogue
China has vowed to play along to the end if Washington's intentions were set on waging a trade war, but urged the US to return to dialogue and cooperation as soon as possible.
"If the United States... persists in waging a tariff war, a trade war, or any other kind of war, the Chinese side will fight them to the bitter end," Foreign Ministry spokesman Lin Jian said.
China will protect its own rights and interests, Lin said, shortly after Beijing announced retaliation to the US tariffs.
