OTTAWA — Prime Minister Mark Carney on Thursday rejected a trade proposal sent overnight by President Trump, dismissing the offer as insufficient and reaffirming Canada’s demand that the United States fully meet five conditions before negotiations can resume.

The rejection, delivered during a brief but pointed press conference in Ottawa, marked a new escalation in the rapidly intensifying economic dispute between the United States and Canada, two of the world’s closest trading partners.

Holding a printed copy of the proposal at the podium, Carney summarized his response in five blunt words: “This proposal is not serious.”

The proposal had been sent earlier in the morning as the Trump administration attempted to prevent further deterioration in the bilateral relationship. In a statement released at 8:34 a.m. Eastern Standard Time, the White House described the offer as a “generous compromise” designed to address Canadian concerns while preserving American interests.

According to details of the proposal later confirmed by officials and media leaks, the United States offered to remove 75 percent of tariffs imposed on Canadian goods during the current dispute. It also proposed restoring intelligence sharing through the Five Eyes alliance and reaffirmed continued cooperation through the North American Aerospace Defense Command, known as NORAD.

In return, the United States asked Canada to suspend its current economic countermeasures, resume energy exports to the United States at previous levels and agree to a 90-day negotiation period aimed at establishing a broader framework for trade and security cooperation.

But within hours, Carney made clear that Canada would not accept the proposal.

Standing before reporters in Ottawa at 12:17 p.m., the prime minister methodically outlined why the offer fell short of Canada’s five previously stated requirements.

“The United States proposes to remove 75 percent of tariffs while maintaining the remaining 25 percent on unspecified sectors,” Carney said. “Canada’s requirement is complete and unconditional removal of all tariffs. Partial compliance is not compliance.”

Carney also criticized the proposal’s language on defense cooperation, saying its commitments to intelligence sharing and NORAD were conditional and lacked the legally binding guarantees Canada had requested.

“Canada will not accept security commitments that can be withdrawn whenever Washington chooses,” he said.

Another central point of contention involves remarks previously made by President Trump suggesting that Canadian provinces might consider joining the United States — statements that provoked strong political reaction in Canada.

Carney said Canada’s third requirement remains a clear public retraction of those comments.

“The proposal contains no explicit retraction,” he said. “Respect for Canadian sovereignty must be stated clearly and publicly.”

Canada has also demanded $14.7 billion in compensation for economic damage caused by tariffs it argues were imposed illegally under international trade rules. The U.S. proposal made no reference to compensation, instead suggesting both countries should “move forward” without revisiting past disputes.

“That is not acceptable,” Carney said.

Finally, the prime minister rejected language requesting that Canada guarantee stable energy exports to the United States, describing it as inconsistent with Canada’s insistence on full sovereignty over its natural resources.

“Canada determines how its resources are sold and to whom,” he said.

The press conference ended abruptly after six minutes. Carney reiterated that Canada’s five requirements remain “clear, specific and non-negotiable,” and said any proposal that fails to meet all of them will be rejected.

“Phase one measures will continue,” he said. “The March 18 deadline stands.”

Financial markets reacted quickly to the breakdown. U.S. stocks fell in afternoon trading, with the S&P 500 dropping more than two percent, while Canadian markets strengthened and the Canadian dollar rose against the U.S. dollar.

In Washington, administration officials scrambled to assess the situation. According to people familiar with internal discussions, national security and economic advisers held an emergency meeting shortly after Carney’s announcement to determine whether the United States should attempt a revised proposal.

President Trump was briefed on the rejection early in the afternoon. According to officials who spoke on the condition of anonymity, he reacted angrily, arguing that the removal of most tariffs represented a major concession and that Canada should have accepted the offer.

Later in the day, the White House issued a statement criticizing Canada’s response.

“Canada’s rejection of a generous American proposal demonstrates that Prime Minister Carney is not interested in resolving this crisis diplomatically,” the statement said.

Some members of Congress, however, took a different view. Several lawmakers said the administration’s proposal did not address the conditions Canada had laid out and urged the president to move more quickly toward a comprehensive settlement.

With just days remaining before the March 18 deadline set by Canada, the standoff has become one of the most serious economic confrontations between the two countries in decades.

Whether the dispute moves toward compromise or deeper escalation may depend on whether Washington chooses to revise its position — or whether Ottawa remains firm in insisting that the United States meet all five of its demands before talks can begin again.