Tehran to win some sanctions relief after four days of talks in the Swiss city of Geneva
Iran and six world powers reached a breakthrough deal on Sunday to curb Tehran's nuclear programme in exchange for limited sanctions relief, in what could be the first sign of an emerging rapprochement between the Islamic state and the West.
Aimed at ending a dangerous standoff, the agreement between Iran and the United States, France, Germany, Britain, China and Russia was nailed down after more than four days of negotiations in the Swiss city of Geneva.
The accord was designed as a package of confidence-building steps to ease decades of tensions and confrontation and banish the spectre of a Middle East war over Tehran's nuclear aspirations.
European Union foreign policy chief Catherine Ashton, who has been coordinating talks with Iran on behalf of the major powers, said it created time and space for talks aimed at reaching a comprehensive solution to the dispute.
"This is only a first step," Iranian Foreign Minister Mohammad Javad Zarif told a news conference. "We need to start moving in the direction of restoring confidence, a direction in which we have managed to move against in the past."
In Washington, President Barack Obama said the deal was an important first step towards a comprehensive solution to Iran's nuclear programme.
The West fears that Iran has been seeking to develop a nuclear weapons capability. The Islamic Republic denies that, saying its nuclear programme is a peaceful energy project.
A senior US official said the agreement halted progress on Iran's nuclear programme, including construction of the Arak research reactor, which is of special concern for the West as it can yield potential bomb material.
It would neutralise Iran's stockpile of uranium refined to a fissile concentration of 20 percent, which is a close step away from the level needed for weapons, and calls for intrusive UN nuclear inspections, the official said.
Iran has also committed to stop uranium enrichment above a fissile purity of 5 percent, a US fact sheet said.
Refined uranium can be used to fuel nuclear power plants - Iran's stated goal - but also provide the fissile core of an atomic bomb if refined much further.
The deal has no recognition of an Iranian right to enrich uranium and sanctions would still be enforced, the US official added.
Iran will get access to $4.2bn in foreign exchange as part of the accord, and is also expected to receive limited sanctions relief on gold, petrochemicals and autos, a Western diplomat said.
British Foreign Secretary William Hague said in a Twitter message that it was an "important and encouraging" first-stage agreement with Iran, whose nuclear programme "won't move forward for 6 months and parts rolled back."
French Foreign Minister Laurent Fabius said the deal only confirmed Iran's right to civil nuclear power.
"After years of blockages, the agreement in Geneva on Iran's nuclear programme is an important step to preserving security and peace," Fabius said in a statement.
US Secretary of State John Kerry and foreign ministers of the five other world powers joined the negotiations with Iran early on Saturday as the two sides appeared to be edging closer to a long-sought preliminary agreement.
The Western powers' goal was cap Iran's nuclear energy programme, which has a history of evading UN inspections and investigations, to remove any risk of Tehran covertly refining uranium to a level suitable for bombs.
Tehran, whose oil-dependent economy has been severely damaged by tightening Western sanctions over the past few years, denies it would ever "weaponise" enrichment.
Diplomacy was stepped up after the landslide election of Hassan Rouhani, a relative moderate, as Iranian president in June, replacing bellicose nationalist Mahmoud Ahmadinejad.
Rouhani aims to mend fences with big powers and get sanctions lifted. He obtained crucial public backing from Supreme Leader Ayatollah Ali Khamenei, keeping powerful hardline critics at bay.
On a Twitter account widely recognised as representing Rouhani, a message said after the agreement was announced, "Iranian people's vote for moderation & constructive engagement + tireless efforts by negotiating teams are to open new horizons."
The OPEC producer rejects suspicions it is trying covertly to develop the means to produce nuclear weapons, saying it is stockpiling nuclear material for future atomic power plants.
Before Sunday's agreement, Israel said the deal being offered would give Iran more time to master nuclear technology and amass potential bomb fuel.
Prime Minister Benjamin Netanyahu told local media in Moscow on Thursday that Iran was essentially given an "unbelievable Christmas present - the capacity to maintain this (nuclear) breakout capability for practically no concessions at all".