The US president was due to meet his Russian counterpart during the upcoming summit for the Group of 20 industrialized nations in Argentina this weekend.

In tweets posted on Thursday after he had departed for the event, Trump said: “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 announcement marks yet another shift in the relationship between Trump and Putin which has repeatedly confounded almost everyone in the world community – including the president’s own intelligence services.

Trump hasn’t been afraid to openly criticize pretty much anyone – Theresa May, fellow Republicans and Oprah to name just a few, but one person conspicuously missing from the list is Vladimir Putin.

In fact with few notable exceptions, Trump has had nothing but glowing praise for the Russian president and has made a number of decisions while in office that appear to have been to his benefit, including refusing to impose sanctions on Russia.

The administration of former president Barack Obama imposed sanctions on Russia for its annexation of Crimea from Ukraine in 2014. That in part brought ties between Washington and Moscow to their lowest point since the end of the Cold War.

Since then, the United States has investigated Russia’s possible interference in the 2016 presidential election that Trump won. Russia has denied meddling and Trump has repeatedly said there was no collusion.

The current situation in Ukraine

On Sunday, the Russian coastguard fired on and seized three Ukrainian vessels trying to pass from the Black Sea into the Sea of Azov through the Kerch Strait, between Russia’s mainland and the Crimean peninsula it annexed from Ukraine.

Both sides are blaming each other for the crisis – Ukraine insisted its vessels were operating in line with international maritime rules, while Russia said they had failed to get permission to pass.

Sailors aboard the vessels seized by Russia have since appeared in videos released by the Kremlin, apparently admitting their ships acted provocatively.

But in at least one of the videos, the crewman appears to be reading lines as he speaks.

Ruptly@Ruptly