In a rare Sunday address, President Obama hailed implementation of the Iran nuclear deal and said it paved the way for the release of other diplomatic breakthroughs, including the release of several Americans held prisoner in Iran and a longstanding dispute between the two countries in international court.

"This is a good day, because once against we're seeing what's possible with strong American diplomacy," Mr. Obama said. "As I said in my State of the Union address, ensuring the security of the United States and the security of our people demands a smart, patient and disciplined approach to the world."

There have been several major developments in the U.S.-Iran relationship over the weekend. On Saturday, the U.S. and Iran announced that four Americans detained in Iran would be released from prison and the U.S. would pardon or drop charges against seven Iranians accused or convicted of violating U.S. sanctions.

Mr. Obama on Sunday called it a "reciprocal humanitarian gesture."

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"These individuals were not charged with terrorism or any violent offenses," the president said. "They are civilians and their release is a one-time gesture to Iran given the unique opportunity offered by this moment and the larger circumstances at play. And it reflects our willingness to engage with Iran to advance our mutual interests, even as we ensure the national security of the United States."

Iran has also promised to cooperate with the U.S. to locate Robert Levinson, the ex-CIA contractor who disappeared in Iran in 2007. The U.S. will drop Interpol "red notices," which amount to arrest warrants, on 14 Iranian fugitives.

"We will never forget about Bob. Each and every day, and especially today, our hearts are with the Levinson family and we will not rest until their family is whole again," Mr. Obama said.

Separate from the deal on prisoners, the U.S. and European Union lifted economic sanctions on Iran after the head of the U.N. nuclear agency affirmed that Iran was in compliance with the landmark nuclear deal reached with six world powers.

"Iran will not get its hands on a nuclear bomb. The region, the United States and the world will be more secure," he said. He reiterated that the deal was "never intended to resolve all of our differences," but said it created "a unique opportunity, a window" for other diplomacy.

"By working with Iran on this nuclear deal we were better able to address other issues," the president said, citing the quick release of U.S. sailors captured in the Persian Gulf earlier this week as well as the prisoner swap.

Iran will be able to immediately recoup about $100 billion in assets frozen overseas. The nation took several steps to curtail its nuclear program - which it insists are for peaceful purposes only - and will submit to monitoring by the International Atomic Energy Agency for up to 15 years. The U.S. and Europe could reimpose sanctions if Tehran violates part of its commitment.

"We've achieved this historic progress through diplomacy without resorting to another war in the Middle East," he said.

On Sunday, the U.S. and Iran also settled a decades-old dispute over funds Iran had used to purchase military equipment from the United States. After years fighting over the claim at the Hague, the U.S. will release the $400 million in funds and an additional $1.3 billion in interest that had accrued since litigation began in 1981. Mr. Obama called the amount of interest "appropriate" and said it was far less than Iran sought.

"This settlement could save us billions of dollars that could have been pursued by Iran so there was no benefit to the Untied States in dragging this out," he said.