NATO (North Atlantic Treaty Organisation) leaders pose for a group photo at the NATO Summit in London, Britain, on Dec. 4, 2019. (Xinhua/Han Yan)

LONDON, Dec. 4 (Xinhua) -- Leaders of 29 member states of the North Atlantic Treaty Organization (NATO) gathered north of London Wednesday for a summit that has been dogged by squabbles, differences and the hurling of insults.

A tranquil golf-resort hotel in Hertfordshire was transformed into a fortress to enable the participants to meet in a heavily secure zone in what had originally planned as a 70th birthday bash for the alliance.

Arguments, however, have set the tone for the much-awaited NATO summit in London, with the Guardian reporting Wednesday that a video has emerged appearing to show world leaders joking at the NATO summit about U.S. President Donald Trump.

The BBC reported that NATO leaders were meeting as tensions between members threatened to overshadow a summit marking the military alliance's 70th birthday.

The highly choreographed anniversary gathering, intended to show unity, has been unable to hide deep differences between member states, BBC's defense correspondent commented.

British media reported that top of the agenda for Wednesday's showpiece meeting would be Turkey's threat to block a NATO plan for the defense of the Baltics and Poland unless NATO denounces the Syrian Kurds, and by extension endorses the Turkish incursion in October into northeast Syria.

Ahead of the three-hour summit starting, NATO secretary general Jens Stoltenberg said a solution to the issue had still not been found.

He told a media briefing: "I'm confident that we will be able to find a solution to the issue related to updating the revised defense plans."

According to the NATO chief, he discussed the issue Tuesday night with Turkish President Recep Tayyip Erdogan. "We are working on the issue as we speak," he said.

This came after Macron's recent comment that NATO is "brain dead".

The main host, British Prime Minister Boris Johnson, glossing over the squabbles, said Wednesday: "There is far, far more that unites us than divides us, and I think one thing every leader here is absolutely resolved upon is the vital importance of NATO for our collective security."