US President Barack Obama said in an interview he is confident sanctions against Iran could be reimposed if Tehran violates an agreement to restrict its nuclear programme.

Obama told National Public Radio (NPR) that US and European negotiators are trying to reach a deal with Iran in which sanctions could be reimposed without a UN Security Council vote, where Tehran-ally Russia would have a veto.

In an excerpt, Obama poured cold water on an Israeli demand that a deal be predicated on Tehran recognizing Israel, when NPR's Steve Inskeep asked Obama about Israeli Prime Minister Benjamin Netanyahu's recent demand.

"The notion that we would condition Iran not getting nuclear weapons in a verifiable deal on Iran recognising Israel is really akin to saying that we won't sign a deal unless the nature of the Iranian regime completely transforms. And that is, I think, a fundamental misjudgement," Obama said.

Obama noted that a nuclear deal could help strengthen moderate elements in Iran.

"We want Iran not to have nuclear weapons precisely because we can't bank on the nature of the regime changing. That's exactly why we don't want to have nuclear weapons. If suddenly Iran transformed itself into Germany or Sweden or France, there would be a different set of conversations about their nuclear infrastructure," Obama said.

He said a reimposition of sanctions would be triggered by a finding of the International Atomic Energy Agency that Tehran had broken the agreement.

After reaching a framework deal last week, negotiators face a 30 June deadline to reach a final agreement meant to prevent Iran from being able to build a nuclear weapon.