US Undersecretary of Defense Elbridge Colby said in a post on X that the Pentagon was "pausing" participation in the Permanent Joint Board on Defense, which was created in 1940.

The move follows President Donald Trump hitting Canada with tariffs and repeatedly calling for the country to become America's 51st state.

Trump has often pushed America's traditional allies to boost military spending and rely less on US protection.

"Unfortunately, Canada has failed to make credible progress on its defense commitments," Colby wrote in a post on X.

"We can no longer avoid the gaps between rhetoric and reality," Colby wrote in a dig at Canadian Prime Minister Mark Carney.

Colby's post linked to Carney's widely-touted January speech at the World Economic Forum in Davos, Switzerland, in which the prime minister declared that the global order was experiencing a "rupture" and that "we largely avoided calling out the gaps between rhetoric and reality."

The board, made up of American and Canadian military and civilian representatives, studies joint defense issues and offers policy recommendations to the two governments.

Under a plan announced by Carney in February, Canada will invest CAN $500 billion (US $360 billion) in its defense industry over the next 10 years.

Carney acknowledged at that time that Canada had not done enough to defend itself in an increasingly dangerous world and that counting on US protection was no longer viable.

"We've relied too heavily on our geography and others to protect us," Carney said.

In April, Jennie Carignan, Canada's top military officer, told AFP she was pleased that military spending had reached two percent of GDP, in line with a NATO target.

The joint board was established in 1940 under US president Franklin Roosevelt and Canadian prime minister William King.