Donald Trump has hit out at Emmanuel Macron with a volley of tweets saying the French were "starting to learn German in Paris" before US intervention in the world wars, rounding off the attack off with a mocking plea to "MAKE FRANCE GREAT AGAIN!"

Mr Trump began with an extraordinary attack on Emmanuel Macron’s call for a “European army” by likening a French defence rapprochement with Germany to the Nazi occupation of France.

Minutes after his online outburst, German Chancellor Angela Merkel gave her unprecedented backing to Mr Macron's defence plans, saying she too wanted a "real true European army", which would complement, but not rival, the Northern Atlantic Alliance, Nato.

In a burst of tweets, Mr Trump also defended his lack of attendance at a World War One memorial event at a cemetery in France at the weekend - he was widely criticised after pulling out due to rain - and threatened wine tariffs in a fully-fledged Twitter rant.

“Emmanuel Macron suggests building its own army to protect Europe against the U.S., China and Russia,” tweeted Mr Trump, just back from the Paris commemorations.

“But it was Germany in World Wars One & Two - How did that work out for France? They were starting to learn German in Paris before the U.S. came along. Pay for NATO or not!”