Iran has proposed what it calls a potential breakthrough plan at talks on its nuclear development programme.
Deputy Foreign Minister Abbas Araghchi said the 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 said.
Iran's uranium enrichment programme is at the core of the six world powers' concerns. It 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 but has resisted international attempts to verify its aims.
Yet 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 with the West.
Britain, the US, Russia, China, France and Germany are eager to test whether those words will translate into real progress such as increased international monitoring and scaling back on Tehran's uranium enrichment.
The first session of the two-day talks in Switzerland - the first since Mr Rouhani's election - lasted more than two hours.
Iran's state TV, which closely reflects government views, said Tehran offered to discuss uranium enrichment levels at the talks. The report also said Iran proposed adopting the additional protocols of the UN's nuclear treaty - effectively opening its nuclear facilities to wider inspection and monitoring - if the West recognizes Iran's right to enrichment uranium.
Of the tons of enriched uranium in Iran's stockpile, most is enriched to under 5% - a level that need weeks of further work to turn into weapons-level uranium. But it also has nearly 200 kilograms of 20%-enriched uranium, a form that can be quickly upgraded for weapons use, according to the U.N's atomic agency.
No final deal is expected at the two-day session. However, if the Iranians succeed in building trust, the talks could be the launching pad for a deal that has proven elusive since negotiations on Iran's nuclear programme began in 2003.