The collapse of negotiations over Iran's nuclear programme would be potentially cataclysmic.
The country’s president is all too aware of the consequences of the meltdown in relations between Russia and the West.
Erdogan is often categorised as a Western ally. This is a misperception. His vision of Turkey is of an emerging great power and regional leader.
Negotiators say a deal over the country's nuclear ambitions is at hand, but trust issues remain.
Turkish Prime Minister Recep Tayyip Erdogan has emerged even more belligerent towards his opponents before the nationwide municipal elections.
The US president tells his Russian counterpart his political strategy is a generation out of date.
Putin has made it clear that the country will no longer cave to the wishes of the US and its allies.
The US has positioned itself firmly behind Japan, raising its huge and powerful neighbour's ire.
Detailed investigations of possible war crimes arising from drone attacks in Pakistan and Yemen pose difficult questions for the US.
Ernest Hemingway immortalised the Paris-based Herald newspaper in his writing, but future readers will know it as the International New York Times.