iran2
Iran and six major world powers reached a nuclear deal, capping more than a decade of on-off negotiations. From left, European Union High Representative for Foreign Affairs and Security Policy Federica Mogherini, Iranian Foreign Minister Mohammad Javad Zarif, Head of the Iranian Atomic Energy Organization Ali Akbar Salehi, Russian Foreign Minister Sergey Lavrov, British Foreign Secretary Philip Hammond and U.S. Secretary of State John Kerry pose for a group picture at the United Nations building in Vienna, Tuesday, July 14, 2015. JOE KLAMAR/AFP/Getty Images

United Nations Secretary-General Ban Ki-moon hailed the Iran deal announced Tuesday as a victory for diplomacy. "I hope – and indeed believe – that this agreement will lead to greater mutual understanding and cooperation on the many serious security challenges in the Middle East," he said in a written statement.

Iranian President Hassan Rouhani said the accord would open “new horizons,” AFP reported, and Foreign Minister Mohammad Javad Zarif referred to the deal as a “win-win” situation. "I believe this is a historic moment. We are reaching an agreement that is not perfect for everybody, but it is what we could accomplish and it is an important achievement for all of us," said Zarif, according to Al Jazeera.

Other world leaders expressed optimism about the agreement and said they feel confident Iran will be prevented from building nuclear weapons. The agreement, if carried out, will end a standoff of more than decade between Iran and Western countries over Iran’s nuclear program. World powers accused Iran of trying to build nuclear weapons, although Iran consistently maintained its program was for peaceful purposes. As part of the deal, Iran will cut its centrifuges from about 19,000 to 6,104, Al Jazeera reported.

As part of the deal, Iran's nuclear program will have to remain peaceful, and in exchange, U.N. sanctions that have crippled the country's economy in recent years will be lifted, EU foreign policy chief Federica Mogherini announced Tuesday. Mogherini said negotiators feel confident that the deal was a good one, though it will undoubtedly be the subject of scrutiny.

Israeli Prime Minister Benjamin Netanyahu, long the most vociferous opponent of any accord, opened a Persian-language Twitter account Monday as a last-minute protest. On Tuesday, he called the decision “a historic mistake for the world,” saying it would ultimately work to advance Iran’s “terror machine.”

U.S. Secretary of State John Kerry called the agreement a "good deal" and said it was a step toward peace. President Barack Obama said the deal "is not built on trust, it is built on verification," the Associated Press reported.