U.S. President Barack Obama says the agreement reached Sunday between Iran, the five permanent members of the U.N. Security Council and Germany, will substantially curb Iran's nuclear program and cut off Iran’s most likely paths to an atomic bomb, in exchange for modest but reversible relief from international sanctions.
Obama said the agreement halts Iran's nuclear program for the first time in nearly a decade, and rolls back key parts of it, paving the way for the next phase of negotiations.
He said the election of Iran's President Hassan Rouhani earlier this year created an opening for intensive diplomacy pursued by the United States and its partners.
The president said, "Today, that diplomacy opened up a new path toward a world that is more secure - a future in which we can verify that Iran’s nuclear program is peaceful, and that it cannot build a nuclear weapon."
A written White House statement detailed what will occur in the first phase, including Iran's commitment to halt enrichment of uranium above the 5 percent level, and to neutralize its stockpile of near 20 percent enriched uranium.
The statement says Iran agrees to not install additional centrifuges of any type, including next-generation centrifuges of major concern to the international community. Centrifuges are used to enrich uranium.
Iran also agreed to leave inoperable roughly half of installed centrifuges at the nuclear site at Natanz, and three-quarters of installed centrifuges at Fordow.
President Obama said Iran has also committed to stopping work at its plutonium reactor at Arak, the focus of intense concern by those opposed to Iran's nuclear ambitions. There will be "intrusive monitoring" of Iran's nuclear program, including daily inspections at Natanz and Fordow.
In return, Iran receives what the agreement calls limited, temporary, targeted, and reversible relief from sanctions. Obama stressed that this modest relief is conditioned on Iran following through on its commitments.
"If Iran does not fully meet its commitments during this six month phase, we will turn off the relief, and ratchet up the pressure," said the president.
Obama said the next phase will be aimed at negotiating a comprehensive solution, and involve what he called the basic understanding that Iran, like other nations, should be able to access peaceful nuclear energy.
But he said, Iran's record of violating obligations makes it necessary for it to accept strict limitations on its nuclear program that will make it impossible to develop a nuclear weapon.
"In these negotiations, nothing will be agreed to until everything is agreed to," said Obama. "The burden is on Iran to prove to the world that its nuclear program will be exclusively for peaceful purposes."
Obama said if Iran seizes this opportunity, it can begin to chip away at mistrust with the United States and have a path for a new beginning with the wider world. If it does not, it will face growing pressure and isolation.
The president also sought to address concerns of Israel and U.S. partners in the Gulf, saying they have "good reason to be skeptical about Iran's intentions."
And he again appealed to members of the U.S. Congress not to move forward with new sanctions, saying doing so would "derail this promising first step" alienate U.S. allies, and "risk unraveling the coalition that enabled sanctions to be enforced on Iran in the first place."