US President Donald Trump has entered a war of words between his French and Turkish counterparts, saying Emmanuel Macron's remark that NATO was brain dead was "very, very nasty" and "disrespectful".

Macron made the comment in a November 7 interview with The Economist, as he criticised a lack of coordination between NATO members over Turkey's recent operation in Syria. Turkish President Recep Tayyip Erdogan later responded, challenging Macron to check his own "brain death".

Trump, speaking to reporters in London on Tuesday alongside NATO Secretary-General Jens Stoltenberg, said Macron's assessment of the military alliance was "insulting to a lot of different forces". Trump also said he would not allow France to take advantage of American companies after a US government investigation found France's new digital services tax would harm US technology companies.

In response, the French government said on Tuesday that France and the European Union are ready to retaliate if Trump acts on a threat to impose duties of up to 100 per cent on $2.4bn in imports of champagne, handbags and other French products. French Finance Minister Bruno Le Maire branded the US threat unacceptable and said the French tax did not discriminate against American companies.

BBC