French Foreign Minister Laurent Fabius said late Saturday night that nuclear talks between Iran and global powers had finished without an agreement but that they would continue at a later date.
"From the start, France wanted an agreement to the important question of Iran's nuclear programme. The Geneva meeting allowed us to advance, but we were not able to conclude because there are still some questions to be addressed," Fabius told reporters early on the fourth day of ministerial talks in the Swiss city.
European Union (EU) foreign policy chief Catherine Ashton will announce that senior political officials, followed by ministers, would meet again to try to clinch a deal, he said.
Ministers from Iran and the major powers held a series of meetings late on Saturday in a final push to hammer out the outline of a deal that would freeze parts of Iran's atomic programme in exchange for sanctions relief.
"Efforts to secure an agreement are continuing with great intensity," a Western diplomat close to the talks said on Saturday before the talks ended.
The latest round of negotiations began on Thursday and U.S. Secretary of State John Kerry unexpectedly arrived on Friday to help narrow remaining differences between Iran and the six nations.
Fabius, British Foreign Secretary William Hague and their counterparts from Russia and Germany, Sergei Lavrov and Guido Westerwelle, also attended, along with Chinese vice foreign minister Li Baodong, demonstrating the six-nation group's commitment to reaching the kind of agreement with Iran that has eluded the West for a decade.
Iranian Foreign Minister Mohammad Javad Zarif said on Saturday that if there was no agreement this weekend, "the process will continue in one week or 10 days".
Fabius told France Inter radio on Saturday that Paris could not accept a "fool's bargain".
His pointed remarks hinted at a rift within the Western camp. A Western diplomat close to the negotiations said the French were trying to upstage the other powers.
"The Americans, the EU and the Iranians have been working intensively together for months on this proposal, and this is nothing more than an attempt by Fabius to insert himself into relevance late in the negotiations," the diplomat told Reuters, speaking on condition of anonymity.
In a further sign that the cordiality that had reigned in the talks so far was dissipating, Iranian Deputy Foreign Minister Abbas Araqchi told Mehr news agency that his counterparts from the six powers "need constant coordination and consultation in order to determine (their) stances".
The main sticking points in the talks include calls for a shutdown of an Iranian reactor that could eventually help to produce weapons-grade nuclear fuel, the fate of Iran's stockpile of higher-enriched uranium, and the nature and sequencing of relief from economic sanctions sought by Tehran.
The powers remain concerned that Iran is continuing to amass enriched uranium not for future nuclear power stations, as Tehran says, but as potential fuel for nuclear warheads.
They are searching for a preliminary agreement that would restrain Iran's nuclear programme and make it more transparent for U.N. anti-proliferation inspectors. In exchange, Tehran would obtain phased, initially limited, relief from the sanctions throttling the economy of the giant OPEC state.
© 2015 Thomson/Reuters. All rights reserved.