European leaders have pushed back at Donald Trump’s ultimatum that they increase defence spending or risk America scaling back its commitment to Transatlantic protection.

Angela Merkel, the German chancellor, said her country would not accelerate existing, long-term plans to ramp up the military budget by 2024 despite a demand by the US this week that countries increase spending by the end of the year.

The president of the European Commission, Jean-Claude Juncker, also said countries must not cave in to US demands.

James Mattis, US defence secretary, earlier this week warned Nato that a new “political reality” after the election of Donald Trump meant it was no longer possible for allies to shirk their share of the defence burden.