VIENNA — Joint efforts by Secretary of State John Kerry and three other Western foreign ministers failed Sunday 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 British Foreign Secretary William Hague after meetings with Kerry and the foreign ministers of France, Germany, and Iran.
Kerry and Hague stayed on for another day of diplomacy. But the major differences remaining strongly indicated that six world powers and Tehran will have to continue negotiations until July 20 and could decide to extend their talks past that informal deadline for a deal.
‘‘We’re working, we’re working, we just got here,’’ said Kerry, when reporters asked about progress in Sunday’s meetings. But he conceded that the two sides have “some very significant gaps.’’
Germany’s foreign minister, Frank-Walter Steinmeier, and Foreign Minister Laurent Fabius of France left Sunday, a few hours after they arrived.
Tehran says it needs to expand enrichment to make reactor fuel but the United States fears Tehran could steer the activity toward manufacturing the core of nuclear missiles. The United States wants deep enrichment cuts; Iran wants to greatly expand enrichment.
Hague and the other foreign ministers said the gap over the enrichment issue is a major one. Steinmeier said he and other ministers had made it clear in meetings with Iranian officials that ‘‘the ball is in 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, 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 Iranian Foreign Minister Mohammad Javad Zarif.
Iran’s hard-liners oppose almost any concession by moderate President Hassan Rouhani’s government.