Tensions bubble to the surface at the G7 summit

Smiles and bonhomie may be on display at the G7 summit in France but bubbling tensions quickly surfaced on Sunday.

It was the first day of talks in Biarritz -- set against a backdrop of worries over a global economic downturn and disunity on a range of matters. One such area: Iran. European leaders have been trying to quell a confrontation between Washington and Tehran since the US withdrew from the Iran nuclear deal.

Late on Saturday, G7 leaders agreed French President Emmanuel Macron should hold talks and pass on messages to Iran. But Donald Trump pushed back, saying he hadn't signed off a statement Macron intends to give on the subject.

In a surprise move, Iran's foreign minister arrived in Biarritz on Sunday -- though a senior Iranian official said he had no plans to hold talks with Trump or any member of the US delegation.

Before leaving Washington, Trump stepped up his trade dispute with China, and at a meeting with UK PM Boris Johnson, Trump said his allies "respect" the tariff war.