Iran's foreign minister made a brief and unannounced visit to the G7 summit in France on Sunday.
Mohammad Javad Zarif attended side-line talks in the seaside town of Biarritz where world leaders, including US President Donald Trump, have gathered.
Reports suggest the US delegation was surprised by his visit, which comes at a time of high tension with Iran.
Mr Zarif said on Twitter that he held "constructive" talks with his French counterpart and the French president.
"Road ahead is difficult. But worth trying," he posted on Sunday evening, adding he gave a joint briefing to German and British officials.
Mr Zarif also met President Emmanuel Macron in Paris on Friday on the eve of the summit.
BBC
Russia's unmanned Luna-25 spacecraft has crashed into the Moon after spinning out of control, officials say.
Donald Trump has confirmed that he will not take part in Republican presidential debates with his rivals in the race for the White House.