WASHINGTON, United States (AFP) — Canadian Prime Minister Mark Carney told United States (US) President Donald Trump that his country was “never for sale” Tuesday as they met at the White House amid tensions on tariffs and sovereignty.

In their first Oval Office meeting, Trump insisted to the recently elected Carney that it would be a “wonderful marriage” if Canada agreed to his repeated calls to become the 51st US state.

But despite Trump’s claims of friendly relations, the body language became increasingly tense between the 78-year-old Republican and the 60-year-old Canadian leader.

“As you know from real estate, there are some places that are never for sale,” Carney told property tycoon Trump, comparing Canada to the Oval Office itself and to Britain’s Buckingham Palace.

“Having met with the owners of Canada over the course of the campaign in the last several months, it’s not for sale. It won’t be for sale, ever.”

Trump then replied: “Never say never.”

Carney won the Canadian election of April 28 on a pledge to stand up to Trump, warning that ties between the North American neighbours could never be the same.

Trump has sparked a major trade war with Canada with his tariffs while repeatedly making extraordinary calls for the key NATO ally and major trading partner to become part of the United States.

Despite that, the two leaders began their meeting with warm words towards each other.

Twice-elected Trump hailed Carney, whose Liberal Party surged from behind to win the election, for “one of the greatest comebacks in the history of politics, maybe even greater than mine”.

But while they expressed a willingness to work towards a trade deal to end the tariffs, it became clear that common ground would be hard to find.