U.S. President Barack Obama has hailed peaceful diplomatic efforts that have led to a nuclear deal with Iran after nearly a decade of tensions.
Mr. Obama spoke late Saturday in Washington after six powers meeting with Iran's representatives reached a set of initial understandings on halting the progress of Iran's nuclear program and rolling it back in key respects.
President Obama said the initial, six-month step includes significant limits on Iran's nuclear program and addresses most urgent concerns, including Iran's enrichment capabilities; its existing stockpiles of enriched uranium; the number and capabilities of its centrifuges; and its ability to produce weapons-grade plutonium using the Arak reactor. The president said, over the next six months, the U.S. and others "will work to negotiate a comprehensive solution."
U.S. Secretary of State John Kerry, speaking in Geneva, said the ultimate goal of the deal is to reach a "comprehensive" agreement with Iran. He said, however, the "core sanctions architecture" remains firmly in place for the next six months.
Iran has also committed to provide increased transparency and intrusive monitoring of its nuclear program, which could have led to a development of nuclear arms.
In return, the United States, China, Russia, Britain France and Germany will provide limited, temporary, targeted and reversible relief to Iran. Major sanctions, including the key oil, banking and financial sanctions will remain in place.
European Union foreign policy chief Catherine Ashton said the deal provides the time and space to try to reach a comprehensive solution to the nuclear standoff between Tehran and the West.
French Foreign Minister Laurent Fabius said the agreement is an important step in preserving "security and peace."
Israel prime Minister Benjamin Netanyahu has been critical of the deal, saying the international community is giving up too much to Iran. However, Kerry said the agreement will make its partners in the region safer. Israel - a key U.S. ally - is an archenemy of Iran.
The deal was reached in the early hours of Sunday morning after more than four days of tough negotiations.
Kerry joined the talks in Geneva earlier Saturday.
The chairman of the U.S. House Committee on Foreign Affairs said he was uneasy with the deal. Ed Royce, a Republican from California, said he has "serious concerns that this agreement does not meet the standards necessary to protect the United States" and its allies.
Swiss Foreign Minister Didier Burkhalter held talks with Iran's foreign minister, Mohammad Javad Zarif on Saturday.
World powers believe Iran's nuclear program can be used to develop nuclear arms and have imposed sanctions on the oil-rich country. Tehran argues that it is developing nuclear power for energy and other peaceful purposes.
European Union foreign policy chief Ashton has been leading the negotiations with the Iranians. The main sticking points have been to what extent Iran will be allowed to enrich uranium and how much sanctions against Tehran would be eased.