The United States on Saturday imposed 50 per cent tariffs on about $20 billion worth of Canadian goods after trade negotiations between both countries failed.

Canada has vowed to retaliate.

The Trump administration announced the tariffs in July over what it called Canada’s “discriminatory treatment of American products.”

Trade negotiators from both countries met for the third day on Friday in Washington, DC, to finalise their trade deal following President Donald Trump’s threat to impose the tariffs.

Mr Trump set a deadline for the negotiations, but negotiators said they had yet to reach an agreement, prompting the tariffs to take effect at 12:01 a.m. Eastern Time (05:01 GMT+1). The deadline was initially set for last Wednesday but was extended.

“We have more work to do. We’re going to continue working up until the last minute. Our job is not finished,” the minister responsible for Canada-U.S. Trade, Dominic LeBlanc, told reporters following talks with U.S. Trade Representative Jamieson Greer.

His comments came shortly after Mr Trump said that the U.S. “should be able to have a deal with Canada.”

In response to the tariff implementation, Canada’s Prime Minister Mark Carney said in a statement that his country would impose retaliatory tariffs.

“Canada will match those tariffs dollar for dollar to protect our workers and businesses,” he said.

“In recent weeks, we made important progress toward improving Canada’s position as having the best deal in the world with the U.S.,” Mr Carney said in a statement. “However, that progress has not been enough to meet our objectives for Canadians.”

He noted that the Canadian government would, in the coming days, implement measures to protect citizens from the impact of the trade war with the U.S.

Mr Greer had announced that Canada “declined to finalise the trade deal under the terms agreed” with Washington, saying it was “a missed opportunity for Canada to partner with the United States.”

“Despite the U.S. offer to Canada to receive the best treatment of any major exporter to our market, new demands and walkbacks of other commitments by Canada have upended the careful balance reached in the past days,” he said.

Five per cent of Canadian products, including electronics, industrial machinery and dairy products, would be affected by the tariffs. The latest tariffs add to existing import taxes on steel, lumber and autos.

Since returning to the White House last year, Mr Trump has slapped Canada with tariffs on key imports, with the neighbouring country retaliating. Since then, both countries have engaged in a cyclical trade dispute, with Mr Trump repeatedly threatening new tariffs.