European countries must follow Britain's lead and spend more on defence to ease relations with the United States, Nato's secretary general has told Theresa May.
In the wake of concerns over the continuing US commitment to the alliance under Donald Trump, Jens Stoltenberg called on countries to hand over more cash to secure the "transatlantic bond".
The Prime Minister, who backs calls for European nations to spend more, insisted the UK will remain a "cornerstone" of Nato.
Mr Trump caused alarm among European allies during the presidential election campaign when he described Nato as ''obsolete'' and suggested the US would not come to the aid of an ally which did not meet the spending target.
Britain is one of just four European members of Nato to hit the target, along with Poland, Estonia and Greece.
During talks at No 10, Mr Stoltenberg hailed Britain for meeting the Nato target of spending more than 2% of GDP on defence.
"By doing so you lead by example," he added. "It's good to see that other allies are now following you and they are starting to increase defence spending.
"They still have a long way to go but are starting to move in the right direction.
"More defence spending in Europe is important for the transatlantic bond, for fair burden sharing between Europe and the United States."
Mrs May said Nato needs to focus on recognising "new threats as they emerge", in particular cyber capabilities.
She added: "The UK wants to remain the cornerstone of the alliance and we very much believe in the alliance and our contribution to it.
"I think as we look in the face of Russian aggression, of course here in the UK we are committed to our 2% of GDP being spent on defence, we are contributing troops to defence of eastern Europe with the Nato operations and our commitment is significant in all of these issues and we've agreed to maintain our nuclear deterrent. "