The EU foreign policy chief Federica Mogherini announced on Thursday that the basis for an agreement for a peaceful Iranian nuclear programme and a lifting of sanctions against Tehran has been reached.

"We have reached solutions on key parameters of a joint comprehensive plan of action," Mogherini said after eight days of talks in Lausanne, Switzerland.

The talks involved Iran, on one side, and the US, UK, France, Germany, Russia and China, on the other.

A comprehensive accord would be drafted by 30 June, she added. As well as curbing Iran's nuclear capabilities, a final deal would also include the 'termination' of nuclear-related economic and financial sanctions imposed by the EU and US.

Under the terms of the deal, Iran would not produce weapons grade nuclear fuel and international monitors will have enhanced access to the country’s nuclear facilities.

Mogherini also said that Iran will retain one uranium enrichment facility at Natanz, while the Fordow nuclear complex would be converted to a nuclear physics and technology center that will no longer enrich uranium.

The EU and the US will release all nuclear-related sanctions only once the International Atomic Energy Agency verifies that Iran has complied with the agreement.

Iran’s Foreign Minister Javad Zarif told reporters after the announcement of the framework deal that none of the agreed measures includes closing any of Iranian nuclear facilities.

Mogherini didn’t say when the international economic sanctions would be lifted. Iran wants them lifted immediately, while the US wants most of them be kept in place until Tehran follows through on terms of the agreement.