President Donald Trump lashed out at his French counterpart Emmanuel Macron, after arriving in Paris to commemorate the end of World War One.
On Twitter, Mr Trump said it was “very insulting” that his host had called for a joint EU army to handle threats from the US, China and Russia.
Mr Macron said on Tuesday that Europe “had to protect itself”.
The two men are currently meeting for scheduled talks ahead of events commemorating the 1914-18 war.
Around 70 world leaders are gathering in Paris for events marking the Armistice that ended World War One, which was signed 100 years ago this Sunday. Read more