US President Donald Trump's meeting with President Putin was set to be the showstopper event in Buenos Aires.He abruptly cancelled it, blaming Russia's refusal to release Ukraine's Navy ships and sailors.The news came just hours after his ex-lawyer Michael Cohen pleaded guilty to lying about the president's business interests in Moscow.President Trump tweeted: "Based on the fact that the ships and sailors have not been returned to Ukraine from Russia, I have decided it would be best for all parties concerned to cancel my previously scheduled meeting in Argentina with President Vladimir Putin.

I look forward to a meaningful summit again as soon as this situation is resolved!"The cancellation soothes concerns over more US cosying up with the Kremlin.

The US and Russian leaders’ last meeting in Helsinki caused outrage when Mr Trump took Mr Putin's denials of election interference over the findings of his own intelligence agencies.Image:Angela Merkel, carrying an umbrella, disembarks from the plane after a faultWorld leaders began landing in Argentina on the eve of the summit on Thursday night.German Chancellor Angela Merkel has faced delays after having to switch planes en route when her aircraft was forced to land shortly after taking off from Berlin after experiencing problems with the electronic systems.French President Emmanuel Macron and President Xi Jinping of China were among some of the first to arrive.Mr Trump’s working dinner meeting with the Chinese leader is now his priority.There's little real hope of a trade war ceasefire - with neither Mr Xi nor Mr Trump wanting to blink first.It's the first time the leaders of the world's two largest economies have met since Mr Trump imposed tariffs on $250bn worth of Chinese imports to force concessions on greater access to Chinese markets and intellectual property theft.Image:China's President Xi Jinping and China's First Lady Peng Liyuan, wave upon arrival in Buenos AiresImage:Emmanuel Macron gave a speech in the cultural centre of the city on the eve of the summitMr Trump is unlikely to bend until there's a decline in US economic numbers, although jittery American markets may add some pressure for an agreement.These global jamborees are not the natural home of an "America First" president.As that infamous Canada G7 image of a recalcitrant, arms crossed Mr Trump, surrounded by his global peers shows - Mr Trump's isolationist foreign policy is never more stark than at these global summits.Mr Trump's unpredictability means the US is no longer the steadying force at these events.Former defence department official Michael Carpenter worked for the Obama administration at previous G20s.He said: "A lot of the policymakers around Trump are going into these meetings themselves not sure what the president is going to say.

Not sure what stance he's going to take on any particular issue and waiting to see what that meeting looks like in person when they are there in the room."For all the security and months of planning and preparation - in the Trump era there's no great hope for consensus in Buenos Aires.On trade, Mr Trump probably won't shift until US economy numbers start to weaken and on climate change - he's only doubling down on his denier status.Traditional loyalties can no longer be relied upon, as Theresa May knows that better than anyone as she seeks global support in Argentina for her Brexit deal which has been publicly panned by the US president.Buenos Aires means fair winds - but if recent summits are anything to go by it could be an ill wind that's about to blow through the Argentinian capital.