Iran has struck a landmark deal with the United States and five world powers to freeze important parts of its nuclear programme. In return, Iran will get limited relief on some economic sanctions.
The breakthrough came during talks in Geneva, and follows a series of high level face-to-face talks between the US and Iran over the past year.
The agreement is being hailed as the most significant development between Washington and Tehran in more than 30 years.
I think is a win-win for both sides. They don't explicitly acknowledge Iran's right to enrich nuclear material, but in fact they can do it .... On the other hand it buys more time to prevent them from having a nuclear breakout … and the most important thing is … the beginning of a normalisation of relations between the United States and Iran.
It is intended to be a first step towards a more comprehensive nuclear pact, to be completed in six months.
Under the deal, Iran has committed to halt uranium enrichment above five percent, limit existing stockpiles of enriched uranium, stop further development of the Arak reactor, and allow increased inspections of its nuclear sites.
In return, the six world powers that make up the so-called P5+1 - the US, Russia, China, Britain, France and Germany - will provide limited relief of some trade sanctions, said to be worth as much as $7bn.
There will be no new sanctions for six months, and Iran will be granted access to some frozen accounts overseas.
The main sanctions on oil, banking and financial systems will remain in place, and all sanctions will be reinstated if Iran violates the terms of this agreement, with the possibility of more sanctions being imposed.
"Today, diplomacy opened up a new path toward a world that is more secure, a future in which we can verify that Iran's nuclear programme is peaceful and that it cannot build a nuclear weapon. While today's announcement is just a first step, it achieves a great deal. For the first time in nearly a decade, we have halted the progress of the Iranian nuclear programme," Barack Obama, the US president, said.
Iran's president, Hassan Rouhani, also welcomed the deal, saying his country had finally won the respect it deserves: "The acknowledgement by world powers concerning this right and the elimination of obstacles in the face of the Iranian nation is of great value. The second achievement is the enrichment right by the Iranian nation on Iranian soil. Whatever the interpretation, this right has been explicitly stipulated by this agreement, stressing that Iran will go on with its enrichment programme."
But Israel condemned the deal, accusing Iran of "deception and self-delusion".
"What was achieved in Geneva is not an historic agreement; it is an historic mistake. Today the world has become a much more dangerous place because the most dangerous regime in the world has taken a significant step toward attaining the most dangerous weapon in the world," Israeli Prime Minister Binyamin Netanyahu told his cabinet.
Can this agreement be considered the greatest foreign policy achievement of the Obama administration? And is this the first step towards resolving a dangerous decade-old standoff?
To discuss this, Inside Story, with presenter Adrian Finighan, is joined by guests: Mohammad Marandi, a political analyst and professor at the University of Tehran; Gerald Steinberg, a professor of political science at Bar-Ilan University and a former Israeli delegate to the International Atomic Energy Agency academic conferences; and Larry Korb, a senior fellow at the Centre for American progress and former assistant US secretary of defence.
"This is an agreement that was reached between the five permanents members of the Security Council plus Germany and Iran. Israel is not at the table and, in fact, Israel is never at the table because no Iranian official will ever sit at the same table with Israel .... Israelis do not see this agreement as providing a framework which will stop Iran. We have six months to see substance, but it seems to be very unlikely, particularly as the sanctions are being reduced without something serious from Iran in return for that."
Gerald Steinberg, a professor of political science at Bar-llan University