NATO was thrown into panic mode yesterday after Donald Trump said the United States would not automatically defend member states in future.

In an explosive New York Times interview, the Republican presidential candidate said he would only come to the aid of other member states if they had “fulfilled their obligations to us.”

When asked if he would defend Baltic states from Russian attack, Mr trump responded: “We have many Nato members that aren’t paying their bills.”

Article five of the North Atlantic Treaty commits all members to come to the aid of an ally under attack.

But the mutual defence clause has become a sword rather than a shield, as Nato has expanded to Russia’s borders and bellicose eastern European states provoke Moscow.

Mr Trump denied he had praised Russian President Vladimir Putin in the past, saying rather: “He’s been complimentary of me.

“I think Putin and I will get along very well,” the White House contender said.

Mr Trump also suggested that he would withdraw US forces — including missile defence units — from Japan and South Korea, saying their presence was jeopardising trade relations in the Far East.

“We are spending a fortune on military in order to lose $800 billion” (£600bn), he said.

White House spokesman Josh Earnest refused to respond directly to Mr Trump’s comments, but he said the US commitment to Nato was “iron-clad.”

Czech Prime Minister Bohuslav Sobotka commented: “Whoever wins the presidential election, I hope the United States will remain a solid Nato partner,” adding that the imperialist military alliance was “the basis of our security.”