Donald Trump is an "idiot" for his criticism of Nato and is making Vladimir Putin "very happy", British MPs have said.
On Saturday, the frontrunner in the race to be the Republican nominee for president told a campaign rally in Wisconsin that the transatlantic military alliance was "obsolete".
Nato celebrates its birthday today. It was founded on this day, April 4, in 1949. Its current secretary general, Jens Stoltenberg, has insisted the alliance remains "strong and united".
Conservative MP Richard Benyon, who sits on the Nato Parliamentary Assembly, said the comments were "another example of Trump making up foreign policy on the hoof".
"It's breathtaking to imagine what this would mean for the most successful alliance in our history. President Putin must be praying for a Trump victory," he told The Huffington Post.
Benyon, a former British Army officer, also sits on the House of Commons defence committee.
Labour MP Mike Gapes, who also sits on the Nato Parliamentary Assembly and is a former chair of the Commons foreign affairs committee also hit out at Trump's comments about the US-European military alliance.
"The man is an idiot and a threat to American, European and international security," he told HuffPost. "Mr Putin must be very happy."
In recent weeks, Trump has sharply criticised Nato, which has been the the cornerstone of transatlantic security since its creation.
However Trump said the US should "be prepared to walk" away from the alliance if other members do not pay more money for its upkeep.
“Either they pay up, including for past deficiencies, or they have to get out. And if it breaks up Nato, it breaks up Nato,” Trump said
"Many countries are not paying their fair share. Many, many of the 28 countries are not paying.
"That means we are protecting them and they are getting all sorts of military protection and other things and they are ripping off the US."
President Obama said said of Trump's latest comments: "The person who made the statements doesn’t know much about foreign policy or nuclear policy or the Korean peninsula, or the world generally."
On Tuesday, Republicans in Wisconsin will vote in that states primary election. Polls have suggested Trump's main rival, Texas Senator Ted Cruz, has a 10-point lead in the state.