New Canadian Prime Minister Mark Carney on Sunday called a snap election for April 28, saying he needed a strong mandate to deal with the threat posed by US President Donald Trump, who "wants to break us so America can own us."

The comments showed the extent to which relations between the US and Canada, two long-time allies and major trading partners, have deteriorated since Trump imposed tariffs on Canada and threatened to annex it as the 51st state.

Although the next election was not due until October 20, Carney is hoping to capitalize on a remarkable recovery by his Liberal Party in the polls since January, when Trump began threatening Canada and former Prime Minister Justin Trudeau announced his resignation.

Upon being sworn in as prime minister on March 14, Carney had said he could work with and respected Trump. On Sunday, however, he took a more combative approach.

"We are facing the most significant crisis of our lifetimes because of President Trump’s unjustified trade actions and his threats to our sovereignty," Carney told reporters after the Governor General - the personal representative of King Charles, Canada’s head of state - approved his request for an election.

"Our response must be to build a strong economy and a more secure Canada. President Trump claims that Canada isn’t a real country. He wants to break us so America can own us. We will not let that happen."

The White House did not immediately respond to a request for comment on Carney’s remarks.

Trump on March 6 delayed a broad 25% tariff on some Canadian goods for 30 days. He has since imposed tariffs on steel and aluminum imports and threatened reciprocal tariffs on additional goods, including Canadian dairy and lumber, on April 2.

LAYING THE GROUNDWORK

"The polling suggests that the number one concern that Canadians have right now is the potential negative fallout of Donald Trump and the threatened tariffs," said Nik Nanos, chief data scientist and founder of pollster Nanos Research.

Carney is "probably setting the groundwork for something a little more strident on April 2nd," Nanos said.

Carney, a former two-time central banker with no previous political or election campaign experience, captured the Liberal leadership two weeks ago by persuading party members he was the best person to tackle Trump.

Now he has five weeks to win over Canadians. On Sunday, Carney proposed cutting the lowest income tax bracket by one percentage point.

Polls suggest the Liberals, who have been in power since 2015 and badly trailed the official opposition Conservatives at the start of the year, are now slightly ahead of their rivals.

"We moved from an election where people wanted change to an election that’s really much more about leadership," said Darrell Bricker, CEO of Ipsos Public Affairs.

"The ability of the Conservatives to attack the Liberals has been greatly diminished, because people are focused on the here and now and the near-term future, not on what happened over the last 10 years," he said by phone.

The Conservatives have sought to portray Carney as an elitist who plans to continue the Trudeau-era policy of high government spending. They also accuse him of being less than clear about how he transferred his personal financial assets into a blind trust.

Carney bristled last week when asked about the trust, and accused the reporter asking of engaging in "conflict and ill will". The prickly reaction could give hope to the Conservatives that Carney might stumble during what will be his first campaign.

Key to any victory will be a good performance in the predominantly French-speaking province of Quebec. Carney had trouble at one press conference when asked to respond in French, first misunderstanding the question and then answering in English.

Conservative leader Pierre Poilievre, on the other hand, speaks flawless French and is a seasoned politician who has fought seven elections.

"What we need to do is put Canada first for a change," Poilievre said at a press conference on Sunday to launch his campaign, adding that his policies, including tax cuts and increased resource production, would bring back investment, helping Canada become more self-reliant and better equipped to stand up to Trump.

Laura Stephenson, a politics professor at Western University in the Canadian city of London, said Carney’s inexperience might not be that important given the Trump factor.

"I have a feeling we’re going to see a little more grace extended than is usually given to politicians during this campaign," she said.

An online Angus Reid poll of 4,009 people released last week put the Liberals on 42% public support and the Conservatives on 37%. Angus Reid said the margin of error was around 1.5%, 19 times out of 20.