PALM BEACH, United States, Jan 7, 2025 (BSS/AFP) - Donald Trump threatened military action to secure the Panama Canal and economic force against neighboring Canada, in a meandering press conference Tuesday a day after Congress certified his election victory.

The Republican billionaire had gathered reporters in southern Florida to announce a $20 billion Emirati investment in US technology but his remarks quickly became a rally-style rant as he returned at length to many of his campaign themes.

"Since we won the election, the whole perception of the whole world is different. People from other countries have called me. They said, 'Thank you, thank you,'" Trump said as he set out his agenda for the coming four years.

But the president-elect hammered President Joe Biden over the 2025 transition, claiming that the White House was "trying everything they can to make it more difficult."

Trump, 78, has not acknowledged his 2020 defeat and refused to participate in the transfer of power to Biden.

On the international stage, the incoming president announced he was planning to rename the Gulf of Mexico the "Gulf of America" and threatened the US's southern neighbor with massive tariffs if it does not halt illegal entries across the border.

He refused to rule out using the military to seize Greenland and the Panama Canal -- both of which he has long coveted -- repeating his criticism of the decision to allow local control of the Central American waterway by then-president Jimmy Carter, who died in December.

Asked if he would use military force to bring Canada to heel, the incoming president said "no, economic force."

As with many of Trump's pronouncements, it was difficult at times to separate humor or bombast from genuine policy, but Trump said eliminating the "artificially drawn" US-Canada border would be a boon to national security.

- Inauguration -
He hammered Biden over the US withdrawal from Afghanistan and US foreign policy in Ukraine and Syria, repeating a familiar false claim that America "had no wars" in his first term.

"We defeated ISIS. We had no wars. Now I'm going into a world that's burning with Russia and Ukraine and Israel," Trump said.

Much of the event was focused on criticism of Biden, whom Trump baselessly accused of being behind the multiple legal challenges he faces -- including the possible release of a federal report into his efforts to overturn 2020 election and sentencing set for Friday in his New York hush money case.

Trump, who returns to the White House on January 20, hit his rival on inflation and vowed to overturn the Democrat's executive order banning offshore oil and gas development off swathes of US coastline.

The press conference came a day after Congress counted and certified Trump's state-by-state electoral college votes, officially naming him the next president, on the fourth anniversary of the 2021 US Capitol riot by a pro-Trump mob.

Trump has promised to pardon many of his supporters who stormed Congress and was asked if that would extend to people who had assaulted police. He dodged the question and claimed falsely that the crowd at the Capitol had been unarmed.