Flight trackers first spotted a jet broadcasting the prime minister’s callsign enroute to the southern US state, in a visit that comes days after Trump threatened the US northern neighbour with import tariffs once he takes office.

According to the website Flightradar, the Canadian leader’s plane landed at the Palm Beach International Airport late in the afternoon.

Canadian public broadcaster CBC said Trudeau would be dining with Trump, and that his public safety minister, Dominic LeBlanc was accompanying him on the trip.

The prime minister’s office did not immediately confirm the unannounced trip.

Trump sent shockwaves across Canada when he announced pending import tariffs against neighbours Canada and Mexico and also rival China in social media posts on Monday.

More than three-quarters of Canadian exports, or Can$592.7 billion (US$423 billion), went to the US last year, and nearly two million Canadian jobs are dependent on trade.

A government source told AFP that Canada is considering possible retaliatory tariffs against the US.

Some have suggested Trump’s tariff threat may be bluster, or an opening salvo in future trade negotiations. But, Trudeau rejected those views when he spoke with reporters earlier in Prince Edward Island province.

“Donald Trump, when he makes statements like that, he plans on carrying them out,” Trudeau said. “There’s no question about it.”