Iranian Foreign Minister Mohammad Jazad Zarif said Saturday that a deal on Iran’s controversial nuclear program was close but it remained unclear if it would be finalized Saturday.

“We have now come to the phase of writing the agreement and we have also agreed on certain issues, but it is not yet clear if we can achieve the result tonight,” Zarif said Saturday evening, following a reported 5-hour trilateral meeting between US Secretary of State John Kerry, EU foreign policy chief Catherine Ashton and himself over the contents of a draft agreement.

“Now we have to work on the details. There are some differences over certain issues,” Zarif added during a break in the meeting, which resumed later Saturday. Zarif’s comments were cited by Iran’s Fars News Agency.

“If we do not reach an agreement tonight, the [nuclear] talks will [resume] in the next seven to 10 days,” he was quoted as saying.

The Iranian foreign minister also held meetings with Russian Foreign Minister Sergey Lavrov and Ashton in efforts to reach an agreement, after which Lavrov and Kerry met.

US Secretary of State John Kerry and Russian Foreign Minister Sergey Lavrov held a bilateral meeting on the sidelines of the P5+1 talks with Iran in Geneva Saturday, November 9, 2013. (Photo credit: Russian Ministry of Foreign Affairs/Twitter)

US Secretary of State John Kerry and Russian Foreign Minister Sergey Lavrov held a bilateral meeting on the sidelines of the P5+1 talks with Iran in Geneva Saturday, November 9, 2013. (Photo credit: Russian Ministry of Foreign Affairs/Twitter)

Earlier, Iran’s deputy foreign minister warned that an initial “first-stage” agreement on Iran’s nuclear program must be reached and signed Saturday or the talks would move to a new round at a later stage.

“The negotiations will not go on tomorrow [Sunday]. Either they end tonight or there is another round,” Abbas Araqchi said, on the third day of negotiations, despite earlier reports that the talks could continue Sunday as world powers and Tehran try to hammer out a breakthrough deal.

“Serious consultations have been held on the text of the final deal, [but] there are still questions that require more negotiations,” he was quoted by AFP as saying.

Iran and six world powers were split on the terms of a nuclear deal because the French were holding out for tougher conditions, a Western diplomat who is in Geneva for the talks told The Associated Press. The diplomat said that five of the six powers were agreed on their demands — with just France demanding stricter terms.

Iranian Deputy Foreign Minister Abbas Araqchi (photo credit: Screen capture YouTube/Press TV)

Iranian Deputy Foreign Minister Abbas Araqchi (photo credit: Screen capture YouTube/Press TV)

French Foreign Minister Laurent Fabius said Tehran was resisting demands that it suspend work on a plutonium-producing reactor and downgrade its stockpile of higher-enriched uranium to a level that cannot quickly be turned into the core of an atomic bomb.

Fabius’s remarks to France-Inter radio were the first to provide some specifics on the obstacles at the Geneva talks. He spoke by telephone from Geneva, where he, Kerry, Lavrov and counterparts from Britain and Germany, who are negotiating with Iran, consulted on how to resolve the obstacles at the talks.

Britain’s Foreign Secretary William Hague took a reserved approach, telling reporters that progress was being made but that it was still too early to know if anything could be finalized Saturday.

“These negotiations have made very good progress and continue to make good progress. But there are still important issues to resolve, so clearly they are not over yet. It’s too early to say that we will reach a successful conclusion today,” Hague was quoted by Reuters as saying.

Israel lobbied hard against the deal on Saturday, with Prime Minister Benjamin Netanyahu and Strategic Affairs Minister Yuval Steinitz reported to have spoken to representatives of some of the P5+1 nations. President Barack Obama called Netanyahu on Friday after the prime minister publicly castigated the emerging deal as “very, very bad” and “dangerous” and said he had pleaded with Secretary of State John Kerry not to sign it. Netanyahu also spoke to Russian President Vladimir Putin.

As Ashton and the other leaders resumed consultations earlier Saturday, the Los Angeles Times reported talks were likely to spill over into next week.

Citing “disappointed” diplomats, the Times said a signing ceremony was not likely to take place on Saturday, even as P5+1 leaders were gearing up for further meetings aimed at narrowing gaps in search of a deal that would offer Iran sanctions relief in exchange for proving its atomic ambitions are peaceful.

Fabius mentioned differences over Iran’s Arak reactor southeast of Tehran, which could produce enough plutonium for several nuclear weapons a year once it goes online. He also said there was disagreement over efforts to limit Iran’s uranium enrichment to levels that would require substantial further enriching before they could be used as the fissile core of a nuclear weapon.

The six powers are considering a gradual rollback of sanctions that have crippled Iran’s economy. In exchange, they demand initial curbs on Iran’s nuclear program, including a cap on uranium enrichment to a level that cannot be turned quickly to weapons use.

Obama said on Friday that the Iranians could be provided with “some very modest relief” in economic pressure, but that the “core sanctions” would remain in place, and pressure could be “cranked” back up if Tehran failed to honor its commitments in the coming months.

Iran, which denies any interest in such weapons, currently runs more than 10,000 centrifuges that have created tons of fuel-grade material that can be further enriched to arm nuclear warheads. It also has nearly 440 pounds (200 kilograms) of higher-enriched uranium in a form that can be turned into weapons much more quickly. Experts say 550 pounds (250 kilograms) of that 20 percent-enriched uranium are needed to produce a single warhead.

Iran says it expects Arak, the plutonium producing reactor, to be completed and go online sometime next year. It would need additional facilities to reprocess the plutonium into weapons-grade material and the U.N’s nuclear agency monitoring Iran’s atomic activities says it has seen no evidence of such a project.

Fabius said Iran is opposed to suspending work on Arak but that suspension was absolutely necessary

Iran is also being asked to blend down “a great part of this stock at 20 percent, to 5 percent,” Fabius said. Uranium enriched to 5 percent is considered reactor fuel grade and upgrading it to weapons-level takes much longer than for 20 percent enriched uranium. He also suggested that the six powers were looking for an Iranian commitment to cap future enrichment at 5 percent.

“We are hoping for a deal, but for the moment there are still issues that have not been resolved,” Fabius said.

Any agreement would be a breakthrough after nearly a decade of mostly inconclusive talks, but would only be the start of a long process to reduce Iran’s potential ability to produce nuclear arms, with no guarantee of ultimate success.

Kerry and his European counterparts arrived in Geneva on Friday with the talks at a critical stage following a full day of negotiations Thursday and said some obstacles remained in the way of any agreement offering sanctions reductions for nuclear concessions.

The presence of Lavrov, and word that Chinese Deputy Foreign Minister Baodong Li also was headed to the talks, provided intense speculation on at least an interim deal.

Netanyahu on Friday insisted the agreement in the making was a “bad deal” that gave Iran a pass by offering to lift sanctions for cosmetic concessions that he said left intact Tehran’s nuclear weapons-making ability. Israel is strongly critical of any deal that even slightly lifts sanctions unless Iran is totally stripped of technology that can make nuclear arms. Netanyahu stressed that Israel was “not obliged by this agreement” and would do “everything” it needed in order to defend itself against the Iranian nuclear threat.

Asked about Netanyahu’s criticism, White House spokesman Josh Earnest said “any critique of the deal is premature” because an agreement has not been reached.

The White House late Friday said Obama called Netanyahu to update him on the ongoing talks and said Obama affirmed he’s still committed to preventing Iran from obtaining a nuclear weapon. The White House said Obama and Netanyahu will stay in close contact.

Kerry tempered reports of progress, warning of “important gaps” that must be overcome.

But Lavrov’s deputy, Sergei Ryabov, was quoted as saying that Moscow expects them to produce a “lasting result expected by the international community.”

According to NBC, Friday’s snap arrival of so many high ranking officials “sparked a high level of anticipation in Geneva, with increased security, including bomb-sniffing dogs, and an influx of the world’s media.”

Israeli officials criticized Obama and the US government as though a deal with Iran was a fait accompli, saying the president “is bringing about a disaster,” Channel 10 reported. The anonymous sources contended that Obama is pressured to arrive at a deal with the Iranians and wants to get the issue off the agenda. The officials, who said Israel opposed any agreement that left Iran with an enrichment capability, were quoted as saying preemptively that Israel rejected the deal taking shape in Geneva.

Netanyahu on Friday described the proposals on the table as the “deal of the century” for Iran, and publicly urged Kerry — with whom he met on Friday morning — not to sign it and to “reconsider.”

Iran considers Russia most receptive to its arguments among the six world powers. For that reason, Lavrov’s presence added additional muscle to efforts to seal a preliminary deal.

In comments to Israeli television on Thursday, Kerry suggested Washington was looking for an Iranian commitment to stop any expansion of nuclear activities that could be used to make weapons, as a first step. “We are asking them to step up and provide a complete freeze over where they are today,” Kerry said.

According to Channel 10, the deal in the works would have the Iranians halt uranium enrichment to 20 percent purity, and their existing stocks of 20% would be converted to fuel rods; enrichment to 3.5% purity would be able to continue at Natanz and Qom. Further, operations at the Arak heavy water reactor would have to cease. In exchange, the channel reported, the Iranians would have sanctions lifted on petrochemical products, gold, auto and airplane parts, and assets worth $3 billion would be unfrozen.

Tehran could be pressing for more significant relief from the sanctions as part of any first-step deal. Iran’s Mehr news agency quoted Iranian delegation member Majid Takht-e Ravanchi as saying his country was asking for an end to sanctions on oil and international banking transactions crippling the ability to repatriate money from oil sales.

Israel has been watching the talks warily from the sidelines. It has frequently dangled the prospect of military action against Iran should negotiations fail to reach the deal it seeks — a total shutdown of uranium enrichment and other nuclear programs Tehran says are peaceful but which could technically be turned toward weapons.

“I understand the Iranians are walking around very satisfied in Geneva as well they should because they got everything and paid nothing,” Netanyahu told reporters. Looking agitated and addressing the media alone — rather than at a traditional joint appearance with the visiting US secretary — he reiterated his opposition to the emerging agreement.