Joint efforts by US secretary of state John Kerry and three other Western foreign ministers have failed to advance faltering nuclear talks with Iran, with the target date for a deal only a week away.
"There has been no breakthrough today," said Foreign Secretary William Hague after meetings with Mr Kerry and the foreign ministers of France, Germany and Iran.
The trip gave Mr Kerry a chance to ease an espionage dispute with Germany. After meeting with German foreign minister Frank-Walter Steinmeier, both stressed the importance of their cooperation in solving global crises, yet offered little indication they have fully mended ties.
Separately, Mr Kerry spoke by telephone with Israeli prime minister Benjamin Netanyahu about the escalating Middle East violence. Like the others, he also met with Iranian foreign minister Mohammad Javad Zarif.
But the dispute over Iran's enrichment programme defied the Western foreign ministers' combined diplomatic muscle.
Tehran says it needs to expand enrichment to make reactor fuel but the US fears Tehran could steer the activity toward manufacturing the core of nuclear missiles. The US wants deep enrichment cuts while Iran wants to greatly expand enrichment.
"There is a huge gap" over enrichment, said Mr Hague, in comments echoed by the other foreign ministers.
The dispute and other differences mean that six world powers and Tehran will continue negotiations until July 20 and could decide to extend their talks past that informal deadline for a deal. Such an agreement would buy time to negotiate a pact limiting the scope of such programmes in exchange for a full end to nuclear-related sanctions against Tehran.
"Obviously we have some very significant gaps still, so we need to see if we can make some progress," Mr Kerry told reporters before a meeting with European Union foreign policy chief Catherine Ashton, who is convening the talks.
"It is vital to make certain that Iran is not going to develop nuclear weapons, that their programme is peaceful. That's what we are here trying to achieve."
French foreign minister Laurent Fabius said "positions are still far apart," and the ministers had come to "try to narrow differences".
Mr Steinmeier said he and other Western foreign ministers had made clear in meetings with Iranian officials that "the ball is Iran's court."
"It is now time for Iran to decide whether they want cooperation with the world community or stay in isolation," he told reporters.
The show of Western unity notwithstanding, Mr Kerry's presence was most important. With the most significant disputes between Washington and Tehran, his visit gave him a chance to discuss them directly with Mr Zarif.
Lower-ranking officials represented both Russia and China, possibly reflecting their view even before today that talks past July 20 are unavoidable.
But Iranian deputy foreign minister Abbas Araghchi suggested any extension would be relatively short, saying "there is not much willingness" by either side to go a full six months. He, too, earlier spoke of "huge and deep differences".