It looked like President Donald Trump was set up for a diplomatic ambush at the Group of Seven summit on Sunday when Iran’s foreign minister suddenly flew into town.

The arrival of the smooth-talking Javad Zarif at the elegant French beach resort of Biarritz, where the leaders of the seven most industrialized democracies are gathered, underscored a key conflict between Trump and the rest about how to deal with Iran’s nuclear ambitions.

Last year, the U.S. pulled out of an agreement that severely limited for several years Iran’s production and stockpiling of nuclear fuel and imposed an extensive inspection regime. Trump claimed the accord forged under Barack Obama was a disastrous deal, and he could do better.

A senior French diplomat told reporters at the G7 summit in Biarritz that Macron informed Trump over lunch on Saturday that Zarif would be coming, and told the rest of the summit participants at dinner that night.

The Trump administration imposed sanctions specifically targeting Zarif earlier this month, but when Trump was asked for a reaction after the the visit became public, his initial comment was, “No comment.”

Although Trump has said he would be willing to meet with Iran’s leaders, they have so far declined, and a tweet from the Iranian foreign ministry stated flatly, “There will be no meetings or negotiations with the American delegation on this trip.”

Trump has insisted he can force Iran to make more concessions, not only about nukes, but about its missiles and extensive proxy forces outside its borders, most notably Hezbollah, and to that end the U.S. has imposed draconian sanctions crippling the Iranian economy while punishing its trading partners.

Germany, France and Britain–all signatories of the Iran deal, and all represented at the G7–have sought desperately to shore up the Joint Comprehensive Plan of Action, as the agreement is called. They share Trump’s view that missiles and proxies are serious issues, but they believe it makes more sense to keep the nuclear agreement that exists rather than throw all the cards up in the air.

To try to keep Iran on board, the Europeans have been discussing various mechanisms to try to bypass the American sanctions, but with little success. Meanwhile, step by calculated step, Iran terminates bits of the JCPOA.

In June, Japanese Prime Minister Shinzo Abe, also at the G7 this weekend, visited Tehran to try to calm the situation, but to no avail. Indeed, holes were blown in a Japanese tanker by mysterious, presumably Iranian, agents at the same time as Abe’s visit.

It’s likely that Zarif’s visit to Biarritz is mainly political theater orchestrated by Macron, and there is little hope it will resolve an increasingly dangerous standoff between the U.S. and Iran. Already we have seen attacks on shipping near the strategic Strait of Hormuz and the recent British seizure, then release against U.S. objections, of an Iranian tanker at Gibraltar.

Last month, when Iran downed an American drone it claimed was over its territorial waters, Trump gave a green light, then a red one, to a retaliatory attack that would have killed a number of Iranian personnel.

Meanwhile, as The Daily Beast has reported, Iran’s clients in Lebanon and Syria, the Hezbollah militias, are preparing for war with Israel as part of a wider conflagration, and Israel is attacking Iranian installations in Iraq as well as Syria.

What Zarif’s visit to the G7 summit might do is calm the situation and buy some time.