A Russian official who spoke on condition of anonymity said the American team put a new suggestion on the table Saturday that seemed to please the Iranian representatives, who said they would take the proposal back to Tehran. The official declined to describe the nature of the U.S. offer.

(Bloomberg) -- An agreement is possible in Iran’s nuclear talks with world powers, both sides said on Saturday, even as the Islamic Republic’s leader said a deal that won’t guarantee the immediate removal of sanctions would be “unacceptable.” 

After six days of discussions in Lausanne, Switzerland, ended without a deal on Friday, U.S. Secretary of State John Kerry said “substantial progress” had been made. Negotiators from the U.S. and five other nations are seeking to ensure that Iran’s nuclear program is peaceful in exchange for relief from sanctions that have hobbled Iran’s economy. 

“We have not yet reached the finish line, but make no mistake, we have the opportunity to try to get this right,” Kerry said Saturday in Lausanne, next to the palatial 19th century hotel where talks took place. “It’s a matter of political will and tough decision-making.” 

Stopping at London’s Heathrow Airport Saturday on his way back to Washington, Kerry met with his European counterparts and Federica Mogherini, the European Union’s foreign policy chief, to discuss the state of negotiations. 

The two sides have given themselves until March 31 to agree on the framework of an accord. The talks have triggered political wrangling in the U.S., where critics of President Barack Obama have accused him of ignoring Iran’s support for international terrorism and rushing to mend ties with a nation that they say seeks to destroy Israel. 

‘Final Step’ 

There were “some novelties in this round of negotiations,” Wang Qun, chief negotiator for China, said without elaborating. He praised the “earnest attitude” and “innovative” thinking in this week’s talks. 

Iranian President Hassan Rouhani blamed the U.S. and other negotiators, which also include diplomats from France, Germany, Britain, and Russia, for the end of Friday’s talks. He said his country was determined to clinch a deal, state-run IRNA news service reported Saturday. 

“It’s possible to reach an agreement, and there is nothing that cannot be resolved,” Rouhani was quoted as saying. “The coming days or weeks will be very tough as taking the final step is always somewhat difficult.” 

Still, Iranian Ayatollah Ali Khamenei said in a speech marking the Persian New Year that the U.S. had “cheated” during the negotiations and that the world powers’ proposal of reducing sanctions only in the months following any potential agreement would be a deal-breaker. 

He said the crowd in the city of Mashhad, some of whom shouted “Death to America,” was right to denounce the U.S. and accused it of trying to divide Iran’s people and its government. 

“Our president has expressly said that the removal of sanctions has to take place immediately when an agreement is reached,” Khamenei said. “The U.S. keeps repeating that we’ll sign a deal with Iran and see if it abides, then we’ll remove the sanctions: this is wrong and unacceptable.” 

High Stakes 

During a tour of the International Olympic Committee museum in Lausanne, IOC President Thomas Bach presented Kerry with a pen bearing the IOC symbol of international understanding. He said he hoped Kerry might be able to use it next week to sign “something important,” a reference to a nuclear agreement. Kerry was headed to London, where he was due to meet his German and French counterparts, as well as European Union foreign policy chief Federica Mogherini. He said the negotiators would meet again next week in Lausanne. 

“The stakes are high and the issues are complicated, highly technical and all interrelated,” Kerry said. “We don’t want just any deal.” 

On Friday, Kerry embraced the visibly distressed Hossein Fereydoun, Rouhani’s brother, who’d just learned that his mother had died. The act of personal diplomacy injected a moment of empathy into the strained relations between two governments that have been at odds for 36 years. 

Personal Diplomacy 

While Fereydoun appeared to welcome Kerry’s gesture, according to photos published online in Iran and credited to the Iranian Students’ News Agency, the image risks igniting a fiery reaction from hard-liners in Tehran, Washington and Israel who oppose a deal and are suspicious of U.S. motives. 

After Iranian Foreign Minister Mohammad Javad Zarif took a 15-minute stroll with Kerry in Geneva in January, he was assailed at home for betraying the 1979 Islamic Revolution. The head of Iran’s paramilitary Basij force, Mohammad Reza Naghdi, accused Zarif of “amateurishness,” and Javad Naghavi Hosseini, the spokesman for the parliament’s national security and foreign policy committee, compared the stroll to treason. 

Negotiations will resume in the second half of next week after a break for Persian New Year, French Foreign Minister Laurent Fabius told Europe1 radio on Saturday. 

Robust Accord 

“If we don’t have a serious accord, then neighboring countries will say ‘why don’t we get nuclear weapons,’” Fabius said. “It’s in everyone’s interest that we have a robust accord, even Iran’s, because otherwise it’s proliferation.” 

The international negotiators have set an end-June target date to sign annexes detailing the steps Iran must take to limit its nuclear capacity and permit international inspections in exchange for relief from the United Nations, EU and U.S. sanctions that have cut oil revenue and battered its economy. 

A Russian official who spoke on condition of anonymity said the American team put a new suggestion on the table Saturday that seemed to please the Iranian representatives, who said they would take the proposal back to Tehran. The official declined to describe the nature of the U.S. offer. 

Russian Deputy Foreign Minister Sergei Ryabkov said the length of an agreement, the pace of sanctions relief and international monitoring remain points of contention. Any draft of a final agreement wouldn’t be circulated until closer to the June 30 deadline, he said in an interview. 

To contact the reporters on this story: Indira A.R. Lakshmanan in Lausanne, Switzerland at 

ilakshmanan@bloomberg.net; Kambiz Foroohar in Lausanne, Switzerland at kforoohar@bloomberg.net; Golnar Motevalli in Tehran at gmotevalli@bloomberg.net

To contact the editors responsible for this story: John Walcott at jwalcott9@bloomberg.netLarry Liebert