In an exclusive interview with The Telegraph last week, Mr Trump said he was strongly considering pulling the US out of Nato.
“Oh yes, I would say [it’s] beyond reconsideration. I was never swayed by Nato. I always knew they were a paper tiger,” he said. Vladimir Putin, the Russian president, “knows that too, by the way”, he added.
Ms Leavitt’s comments came a day after Mr Trump announced a two-week ceasefire with Iran, subject to the regime reopening the Strait of Hormuz.
The president has long had a fractious relationship with Nato, repeatedly claiming the US has been “ripped off” by member states who refused to meet defence spending targets.
However, he has been mollified by Mr Rutte’s diplomacy, and the fact that all Nato allies, with the exception of Spain, have agreed to spend 5 per cent of their GDP on defence.
Mr Trump has repeatedly said he would not defend allies who leave the burden of military spending to the US.
During the 2024 presidential election, he said he would encourage Russia to do “whatever the hell they want” to countries who did not meet their obligations.
Nato has faced repeated crises since Mr Trump returned to power last year, most acutely when he threatened to annex the island of Greenland from Denmark, an alliance member.