'Today is a good day' Obama said in a White House address to the nation after US prisoners were released from Tehran and key aspects of a nuclear deal were implemented.

"For decades our differences meant our governments almost never spoke to each other. Ultimately that did not advance America's interests' Obama said in comments aimed at a skeptical US public.

'We achieved this through diplomacy without resorting to another war in the Middle East."

His comments follow a momentous day that saw international inspectors confirm that Iran had hobbled a nuclear program that had been decades in the making costly to build and the source of extreme national pride.

The United States responded by easing decades of sanctions that have crippled Iran's economy and kept it out of the global economy.

The United States unfroze an estimated $100 billion of Iranian assets held abroad and settled a long running international dispute that will see Iran get $1.7 billion directly from Washington.

Simultaneously Washington and Tehran unveiled a prisoner swap deal that released high-profile American prisoners.

The detention of five Americans including Washington Post journalist Jason Rezaian -- had been particularly contentious in the United States a uncomfortable echo of the 1979 hostage crisis which severed relations.

Obama hailed the release of five Americans who had been held in Iran as three of them were on their way to Switzerland.

"When Americans are freed that's something we can all celebrate" Obama said.

"I've met with some of their families. I've seen their anguish. How they ache for their sons and husbands. I gave these families my word. I made a vow that we would do everything to win the release of their loved ones and we have been tireless."

- Unclear path ahead -Obama said that the United States would continue to have problems with the Iranian government's "destabilizing activities' in the region including support for militant groups.

That has been a primary focus for Republicans who have been deeply critical of Obama's policy as the United States heads to elections in November.

Obama insisted the United States would "not waiver' in defense of its security or that of its allies and partners.

But there was also an olive branch to Iran's young and growing population.

'I do want to speak directly to the Iranian people' Obama said.

"Yours is a great civilization with a vibrant culture that has so much to contribute to the world in commerce and science and arts.'

"For decades your government's threats and actions to destabilize the region has isolated Iran from much of the world. Now our governments are talking to each other.'

"Following the nuclear deal you especially young Iranians have the opportunity to build new ties with the world. We have a rare chance to pursue a new path.'arb/jm