US Secretary of State Mike Pompeo crashed a meeting of European foreign ministers in Brussels today to push for a united transatlantic front against Tehran and its nuclear programme.
But he failed to bend attitudes among leaders who fear the US and Iran are inching towards war.
Pompeo's last-minute decision to visit the EU capital, announced as he boarded a plane from the US, set up a confrontation between the US secretary and European diplomats who have been scrambling to save the 2015 Iran nuclear deal.
At least one, British Foreign Secretary Jeremy Hunt, said he feared that unintentional escalation from the US and Iran could spark a conflict - an unusually bold statement that appeared to assign equal culpability to Washington and Tehran.
The visit came on a day that the Saudi Foreign Ministry said two of its oil tankers were attacked and damaged off the coast of the United Arab Emirates. Saudi Arabia did not assign blame for the attack, but the announcement contributed to fears of open aggression in the region.
Pompeo was rebuffed on even some basic requests in Brussels.
European diplomats haggled over how much to accomodate him while his plane sped across the Atlantic. The EU's chief diplomat, Federica Mogherini, coolly announced she had a busy day and that the pair would talk "if we manage to arrange a meeting." She found the time.
The top diplomats of Britain, France and Germany agreed to meet one-on-one with Pompeo but would not allow the Americans the symbolic victory of a group meeting. The Europeans - they're diplomats, after all - blamed the decision on scheduling difficulties.
The Trump Administration has called for "maximum pressure" against Iran. Mogherini reached for a different extreme after meeting with Pompeo.
"The most responsible attitude to take," Mogherini said, "should be that of maximum restraint and avoiding any escalation on the military side."
US diplomats downplayed talk of a split.
"We agree on much more than we disagree. That continues to be the case," said Pompeo's top Iran adviser, Brian Hook. "We share the same threat assessment. We are very concerned about Iran's - a lot of the multiple threat streams that have been reported over the last three or four days."
But the Europeans said they are fearful about the behaviour of both Iran and the Trump Administration.
"We are very worried about the risk of a conflict happening by accident, with an escalation that is unintended really on either side," said Hunt.
"Most of all, we need to make sure we don't end up putting Iran back on the path to renuclearisation. Because if Iran becomes a nuclear power, its neighbours are likely to want to become nuclear powers. This is already the most unstable region in the world, and this would be a massive step in the wrong direction."
Iranian leaders announced last week that they would scale back their cooperation under the agreement, in essence forcing Europe to choose between defying Washington or kissing the nuclear deal goodbye. Europe considers the deal key to preventing a nuclear-armed Iran. President Donald Trump withdrew the US from the deal in May 2018.
Pompeo scrapped a day of mostly ceremonial events in Moscow in favour of the Brussels stopover. He plans to meet Russian President Vladimir Putin and Foreign Minister Sergei Lavrov in the Black Sea resort of Sochi tomorrow.