Intelligence sharing among NATO countries is in danger as members become increasingly wary of one another, and the earthquake unleashed by US President Donald Trump risks making things worse, current and former alliance and security officials from across the alliance told Politico, the latter reports.

There have long been strains caused by distrust between the alliance's traditional Western members and newcomers from the ex-communist east. That grew worse following Russia's attack on Ukraine, when pro-Russia Hungary, joined recently by Slovakia, are seen as unreliable, said eight current and former NATO and security officials with knowledge of intelligence sharing at the alliance.

But now the US shift toward Russian under Trump is shaking the core of the alliance—prompting countries to wonder about the risk of sharing intelligence with Washington, said five of the officials.

The confusion around the reliability of the US worsened this week, with reports that it temporarily cut off intelligence sharing with Ukraine to put pressure on Kyiv to come to the negotiating table with Russia.

“There are a lot of whispers in the halls of NATO about the future of intelligence sharing within the alliance,” said Julie Smith, U.S. ambassador to NATO under Joe Biden until November, adding she had “heard concerns from some allies” on whether Washington will continue to share intel with the alliance.

According to Daniel Stanton, a former official at Canada’s foreign intelligence service CSIS, “at a time when they actually need more intelligence, there will be less going into it.”

"Intelligence folks can share and talk to each other under conditions that others cannot," said another official. "We haven’t seen any reduction in that.”

Intelligence sharing among NATO's 32 members has never been as close as among Five Eyes, mainly because of fears of leaks and suspicions that some national intelligence agencies could have been penetrated by the Russians.

Sharing intelligence can be very powerful, as happened when the Biden administration trumpeted about Russia’s preparations to attack Ukraine, which played a decisive role in alerting allies and rallying a response.

But three years on, and with a decisive political shift under Trump, the future role of US intelligence is in question.

“The question now is whether intel sharing will remain a key feature of transatlantic work at NATO, given the questions allies have about whether or not the U.S. is impartial in its handling of the war in Ukraine and future negotiations,” said Julie Smith, US ambassador to NATO from 2021 to 2024.