Declaring that Iran no longer wants to “walk in the dark” of international isolation, Iranian negotiators put forward what they called a potential breakthrough plan Tuesday at the long-stalled talks on easing fears that Tehran wants atomic arms.

Deputy Foreign Minister Abbas Araghchi said the Iranian plan’s formal name was “An End to the Unnecessary Crisis and a Beginning for Fresh Horizons.” He described it as having many new ideas but added negotiators had agreed to keep the details confidential during the morning bargaining session.

“We think that the proposal we have made has the capacity to make a breakthrough,” he told reporters.

Alluding to the international pressure because of Iran’s nuclear program that has driven the country into near-pariah status, he said: “We no longer want to walk in the dark and uncertainty and have doubts about the future.”

Iran’s version of a grand bargain is for painful international sanctions to be lifted in exchange for possible concessions it had been previously unwilling to consider such as increased monitoring and scaling back on uranium enrichment — a potential path to nuclear arms and the centerpiece of the impasse with the West.

European Union official Michael Mann said Iran’s PowerPoint presentation, presented by Foreign Minister Javad Zarif, lasted about one hour.

The session resumed in mid-afternoon and a U.S. State Department official said the five powers were looking at further details of the Iranian presentation. The official demanded anonymity because she was not authorize to divulge details of the closed meeting.

Iran’s uranium enrichment program is at the core of the six world powers’ concerns. Iran now has more than 10,000 centrifuges churning out enriched uranium, which can be used either to power reactors or as the fissile core of a nuclear bomb. Iran has long insisted it does not want nuclear arms — a claim the U.S. and its allies have been skeptical about — but has resisted international attempts to verify its aims.

Tehran is now under international sanctions that are biting deeply into its troubled economy. Since the election of reformist Iranian President Hassan Rouhani in June, Iranian officials have said they are ready to compromise.

The U.S, Russia, China, Britain, France and Germany are eager to test whether those words will translate into real progress such as increased international monitoring and scaling back uranium enrichment.

“We have seen some positive mood music coming out of Tehran,” Mann said. “But of course the most important thing is that they actually follow it up with concrete proposals that address our concerns.”

The first session of the two-day talks — the first since Rouhani’s election — lasted about 2 ½ hours, ending shortly after noon. Back pains suffered by Zarif, Iran’s chief negotiator, threatened to complicate the process.

Mann said the pains did not stop Zarif from having a “cordial” dinner Monday evening with Catherine Ashton, the top EU diplomat convening the talks. But Araghchi said Zarif was “suffering a lot,” although he intended to stay in Geneva until the talks ended.

Iran’s state TV, which closely reflects government views, said Tehran offered to discuss uranium enrichment levels. The report also said Iran proposed adopting the additional protocols of the U.N.’s nuclear treaty — effectively opening its nuclear facilities to wider inspection and monitoring — if the West recognizes Iran’s right to enrich uranium.

No final deal is expected at the two-day session, but it potentially could be the launching pad for a deal that has proven elusive since negotiations began in 2003.