While world powers hailed a landmark deal on 14 July to curb Iran's nuclear programme in exchange for billions of dollars in relief from international sanctions, one Washington analyst said it may take years to see if the deal will improve US-Iran relations.

"Iran certainly will prioritize relations with Russia, China and India, and perhaps some countries in the European Union," says Jon Alterman, director of the Middle East Program, at the Center for Strategic International Studies.

"Whether this leads to some sort of thaw with the US, whether the anti-Americanism that has been so important to the Iranian revolution, and to the Iranian political coherence diminishes, I think it's something that's very hard to read."

Alterman says that while the deal will curtail the proliferation risk posed by Iran, it does little to help address regional issues, in countries where the US sees Iran as a major destabilizing force.

"Those issues range from Yemen to Lebanon to Syria and elsewhere," said Alterman. "What the Obama administration hopes and what the Iranian government has promised is if we can cooperate on this, then we can cooperate on any number of things. Whether in fact it turns out we cooperate on a wide range of things or whether it gives the Iranians a sense of impunity and actually worsens Iranian behaviour, is something we're just going to have to judge in the next several years."

Under the deal, sanctions imposed by the US, European Union and United Nations will be lifted in return for Iran agreeing to long-term curbs on a nuclear program that the West has suspected was aimed at creating a nuclear bomb.

Iran will mothball for at least a decade the majority of its centrifuges used to enrich uranium and sharply reduce its low-enriched uranium stockpile.

The agreement is a political triumph for both US President Barack Obama, who has long promised to reach out to historic enemies, and Iranian President Hassan Rouhani.

"What President Obama is saying is that you can create incentives for a different Iranian relationship with the world, which in the longer term will make the world safer, and maybe even improve lives for a whole range of Iranians, not just Iranians in the regime who are benefiting from the sanctions, but ordinary Iranians who would say our country's interest is having a positive relationship with the world, not a negative relationship with the world. That this sort of isolation we've been going through for 35 years, doesn't really serve Iranian national interests," said Alterman.

For Obama, the diplomacy with Iran, begun in secret more than two years ago, ranks alongside his normalisation of ties with Cuba as landmarks in a legacy of reconciliation with foes that tormented his predecessors for decades.

"As President Obama said, the only way to judge this deal is not going to be right now, it's going to be in 10 years' time," added Alterman.

The White House said on Tuesday that it will take a couple of days to send the documents of the Iran nuclear deal to the US Congress for review.