President-elect Trump on Monday reiterated his suggestion that Canada should become the 51st U.S. state, just hours after Prime Minister Justin Trudeau announced his plan to resign.

"Many people in Canada LOVE being the 51st State. The United States can no longer suffer the massive Trade Deficits and Subsidies that Canada needs to stay afloat. Justin Trudeau knew this, and resigned," Trump wrote on Truth Social. 

"If Canada merged with the U.S., there would be no Tariffs, taxes would go way down, and they would be TOTALLY SECURE from the threat of the Russian and Chinese Ships that are constantly surrounding them. Together, what a great Nation it would be!!!" he added. 

Sources told Fox News in December that Trump brought up the merger idea to Trudeau in person when the pair met at Mar-a-Lago in late November. 

CANADA’S TRUDEAU ANNOUNCES RESIGNATION FOLLOWING PARTY PRESSURE AMID CRITICISMS OF TRUMP, BUDGET HANDLING 

Trudeau jetted to Trump’s Florida residence unannounced that month after the president-elect threatened to impose sweeping tariffs on Canadian products. Trump is warning of 25% tariffs on Canada and Mexico over failures by both nations to curb the flow of illegal immigrants and illicit drugs from those countries into the U.S.  

"We discussed many important topics that will require both countries to work together to address, like the fentanyl and drug crisis that has decimated so many lives as a result of illegal immigration, fair trade deals that do not jeopardize American workers and the massive trade deficit the U.S. has with Canada," Trump wrote on Truth Social at the time. 

Trudeau announced earlier this morning that he will resign as prime minister and as the leader of Canada’s Liberal Party. 

TRUMP PLANS TO ‘IMMEDIATELY’ REVERSE BIDEN’S ‘RIDICULOUS’ BAN ON NEW OIL AND GAS DRILLING ALONG US COAST 

"I intend to resign as party leader, as Prime Minister, after the party selects its next leader through a robust nationwide competitive process," Trudeau said in a Monday morning address. "Last night, I asked the president of the Liberal Party to begin that process. This country deserves a real choice in the next election, and it has become clear to me that if I'm having to fight internal battles, I cannot be the best option in that election." 

Trudeau, who has led Canada for nearly a decade, has been grappling for months with significant drops in his approval ratings over mounting frustration relating to issues like the soaring cost of living and rising inflation.  

The long-time prime minister saw an increase in calls for his resignation — from at least seven Liberal Members of Parliament as well as opposition party leaders — following the abrupt departure of his finance minister, Chrystia Freeland, who wrote a scathing letter of resignation mentioning Trudeau's handling of certain economic policies as well as the threats levied by Trump. 

Fox News’ Michael Dorgan, Caitlin McFall and Danielle Wallace contributed to this report.