NATO members thought they were celebrating the 70th anniversary of the alliance, what transpired was an acrimonious birthday bash full of hot mic moments, jokes about returning Daesh militants and an impeachment cloud hanging over President Trump.

World leaders watch a marching band perform as they pose for the family photo at the NATO summit at the Grove hotel in Watford, northeast of London on December 4, 2019.
World leaders watch a marching band perform as they pose for the family photo at the NATO summit at the Grove hotel in Watford, northeast of London on December 4, 2019. (AFP)

The leaders of the world's most powerful military alliance clashed over personality and policy on Wednesday as NATO's summit ended with an effort to paper over their sharp divisions.

Trump eschewed a press conference after footage emerged of foreign leaders mocking the US president at an after-dinner.

Meeting outside London to mark the 70th year of the Atlantic alliance, the members vowed to stick together against threats from Russia and terrorism and recognised the challenge of a rising China.

But the bad blood continued to the end of the two-day get-together, with US President Donald Trump branding Canada's Prime Minister Justin Trudeau "two-faced" after a group of allied leaders were caught on video at a Buckingham Palace reception mocking the US leaders' rambling press appearances.

Trump exasperated divisions by only meeting NATO leaders who are paying 2 percent of their GDP for their defence spending.

Simon McGregor-Wood reports from the NATO meeting.

Trump cancelled his planned final news conference to fly directly back to Washington and into a political storm as opposition Democrat lawmakers issued a report calling for his impeachment.

Despite his anger, he appeared content with the result of the summit, boasting of having convinced his European allies to boost defence spending and Turkey to drop its objections to the adoption of an updated defence plan for the Baltic states and Poland.

The second day of the get together began with the release of a video showing Trudeau, France's President Emmanuel Macron, Britain's Prime Minister Boris Johnson and the Netherlands' Mark Rutte joking together about how Trump had delayed the previous days meetings.

Trump was furious, and criticised the Canadian leader for not meeting NATO members' target of spending two percent of GDP on defence.

'Braindead' 

The run-up to the summit had been marked by Macron branding the alliance "brain dead" and demanding a new strategy, reopening a dialogue with Russia and refocusing on the fight against terrorism.

Afterwards, Macron stood by his incendiary language, declaring: "I am happy to have launched the debate, it seemed to me indispensable."

Turkey's President Recep Tayyip Erdogan stopped short of withholding approval for an updated Baltic defence plan unless his allies agreed to brand the YPG which is an affiliate of the PKK, a recognised terrorist organisation from also being recognised as a terrorist outfit.

Macron rejected Ankara's call, saying that he was sensitive to Turkish concerns about terror.

Despite the rancour, the 29 managed to agree on a "London Declaration" and Erdogan withdrew his objections after an unscheduled side meeting with Trump.

"In challenging times, we are stronger as an alliance, and our people safer," the declaration said.

"Our bond and mutual commitment have guaranteed our freedoms, our values, and our security for 70 years."

The statement was the first from NATO to acknowledge the growing strategic challenge posed by China, and also stressed the need for a stronger coordinated response against terrorism.

It held out the possibility of "a constructive relationship with Russia when Russia's actions make that possible" but stressed the threat posed by Moscow's deployment of intermediate-range nuclear missiles.

And, in a nod to French and German concerns about NATO's strategic direction, the members asked Secretary General Jens Stoltenberg to consult experts to strengthen the alliance's "political dimension".

'Very nasty'

In recent weeks Macron tried to shake up the agenda by demanding a review of alliance strategy, but Trump hit back.

"I think that's very insulting," Trump said of Macron's assertion last month that NATO is experiencing "brain death".

"Nobody needs NATO more than France," he warned. "It's a very dangerous statement for them to make."

Trump has defended Stoltenberg's record of pushing allies for increased defence spending, but he reiterated his own long-standing complaints.

Only nine of NATO's 29 members have reached the target agreed at its 2014 summit to spend two percent of their GDP on defence before 2024.

Trump, who cited in particular Germany as falling short for spending only 1.2 percent of GDP, held lunch talks with the so-called "two percenters".

Source: TRTWorld and agencies