Poland, a NATO member on the alliance's eastern flank, is one of the staunchest supporters of neighbouring Ukraine, which has been struggling to fend off Russia's invasion launched in 2022.

Trump, who will be sworn into office on Monday, has promised to cut a deal to bring a quick end to the war, sparking fears he could force Kyiv to make painful concessions to Moscow.

Tusk on Friday vowed to secure "the closest possible cooperation with the United States, with Canada, both in the context of the war in Ukraine, but also more broadly".

Speaking alongside British Prime Minister Keir Starmer, Tusk added that both leaders would work on the transatlantic ties to be "at the highest possible level, regardless of the sometimes objective difficulties or uncertainties".

Tusk and Starmer also announced the launch of negotiations on "a new UK-Poland security and defence treaty".

"This includes deepening ties between our defence industries," Starmer told reporters.

Trump has demanded that NATO members increase defence expenditure to five percent of GDP, even though the alliance's current minimum level for defence spending is two percent.

Poland plans to spend 4.7 percent of its annual economic output on defence in 2025.

"It is not my task to call on NATO partners to follow Poland's lead when it comes to military spending, I am not here to lecture anyone," Tusk said.

"But there is no doubt that the position of the aggressor... would be incomparably worse if capabilities of the individual NATO countries were greater today and if they corresponded to our real economic potentials," he added in reference to Russia.

In recent years Poland signed a string of contracts with the United States for US-designed army equipment, including Apache attack helicopters and modern Abrams tanks.

Poland also hosts more than 10,000 US troops stationed on its territory.

mmp/bc

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