'Key parameters' of Iranian nuclear deal agreed in Switzerland

"Key parameters" of a nuclear deal have been agreed and will be finalised by June 30, President Rohani announced in a tweet.

A Western source said the framework agreement included provisions for two-thirds of Iran’s current enrichment capacity to be suspended and monitored for the next decade. Most of Iran’s enriched uranium will either be diluted or shipped abroad for storage.

"Found solutions, ready to start drafting immediately," said Iran's Foreign Minister Javad Zarif, also in a tweet.

Iranian media reported that Tehran had agreed to slash the number of its centrifuges from 19,000 to 6,000.

US sources said the draft deal included provisions for US and EU sanctions to "snap back into place" if Iran fails to uphold its part of the agreement.

Sanctions have halved Iran’s oil exports to just over one million barrels per day since the last round of sanctions was put in place in 2012, and how to revoke them – and whether they could be reinstated – had proved a major sticking point in the talks.

"Sanctions that are lifted can be re-imposed if the deal is not applied," the office of President François Hollande said in a statement. A "credible" and "verifiable" final agreement must prevent Iran from ever developing a nuclear weapon, the Elysée Palace said.

US Secretary of State John Kerry tweeted that the deal would “resolve major issues on the nuclear program”.

“Back to work soon on a final deal,” he added.

French Foreign Minister Laurent Fabius also struck a cautious note, welcoming the framework but adding: "There is still work to do."

Iran’s Zarif and EU foreign policy chief Federica Mogherini delivered a joint statement late Thursday following reports of the deal. Mogherini has acted as a coordinator for the P5+1 powers – the United States, Britain, France, China, Russia plus Germany – in the latest round of talks with Tehran.

Mogherini said a “decisive step” had been achieved.

The design of a new Iranian reactor will be altered so that no weapons-grade plutonium can be produced, Mogherini said. The Fordo facility, built deep inside a mountain, will remain operational but will not be used for enrichment but for research and development.

Zarif said the agreement would show that "our programme is exclusively peaceful, has always been and always will remain exclusively peaceful", while not hindering the country's pursuit of atomic energy for civilian purposes.

Russia praised the deal as one that respects “Iran's unconditional right to a peaceful nuclear programme”, the foreign ministry said in a statement.

Speaking from the Rose Garden at the White House, US President Barack Obama said that a "historic understanding" had been reached with Iran.

He called the draft agreement "a good deal, a deal that meets our core objectives".

(FRANCE 24 with REUTERS, AFP and AP)