President Donald Trump has hit out at Canada after Prime Minister Mark Carney rejected a proposed U.S.-Canada trade agreement and pledged dollar-for-dollar retaliation against new American tariffs.

In his first public comments since the negotiations collapsed, Trump wrote on Truth Social: “Canada wants the benefits of being a State, without being one.”

“They have also charged our great farmers, for many years, massive amounts of Tariffs. No more!!!” he added in the early morning post.

Carney said Trump’s new 50 percent tariffs on $20 billion worth of Canadian goods was an economic “attack” on Canada and vowed retaliatory tariffs to take effect next month. Newsweek has contacted Global Affairs Canada and the White House for comment outside of office hours.

During his presidency, Trump has wielded the threat of tariffs, a tax on imported goods, in particular targeting Canada.

Trade talks between Ottawa and Washington broke down on Friday with Carney calling last-minute changes in the U.S. proposed terms “unfair, uneconomic, and called into question the reliability of any deal."

Canada sends 72 percent of its goods exports to the U.S. and so tariffs will upend one of the world’s most entwined trading relationships.

Trade talks had been taking place since July, after Trump threatened to impose a 50 percent levy on nearly $20 billion of Canadian imports by 19 August. The president paused the tariffs last week saying that both sides were close to a deal.

But Carney said that though there had been progress in talks this was "not enough to meet our objectives for Canadians".

He added that he suspended trade negotiations and directed negotiators to return to Ottawa.