Ivo Daalder, the former US ambassador to Nato, also took issue with Mr Trump’s claims and replied directly to the president on Twitter.
“I’m sorry, Mr President but that is not how Nato works,” he said, pointing out that Nato spending was not a “financial transaction” between countries but a joint commitment to spend two per cent of GDP on defence.
But the USA spends over 4% of its GDP on defense.
Ivo Daalder on Twitter
4/ Those who currently don’t spend 2% of their GDP on defense are now increasing their defense budgets. That’s a good thing.
He went on to argue that America’s large military commitment to Nato was not a “favour to Europe” but a mutually beneficial arrangement, because keeping Europe “whole and free” was key to US interests.
Mr Trump has clashed with Germany in the past as it currently spends just 1.18 per cent of GDP on defence, according to the latest figures.
But the president’s stance on Nato appears to have softened slightly since the election campaign, when he rejected the military alliance as “obsolete”.