United States President Barack Obama has defended a framework nuclear understanding with Iran as a once-in-a-lifetime opportunity to prevent Iran building a nuclear bomb and bring longer-term security to the Middle East, insisting the US will stand in defence of Israel.

In an interview with The New York Times, published on Sunday night, Obama argues the risks of a deal are far outweighed by potential gains if it deters Iran's nuclear weapons aspirations, since the US is a far superior military power who can protect its core security interests.

He said the US will make sure the deal does not threaten Israel's own military advantage.

The notion that Iran is undeterrable is "simply not the case", Obama told The Times.

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"And so for us to say, 'Let's try' - understanding that we're preserving all our options, that we're not naive - but if in fact we can resolve these issues diplomatically, we are more likely to be safe, more likely to be secure, in a better position to protect our allies."

'Committed to Israel'

Obama added that he was "absolutely committed" to making sure Israel maintains "their qualitative military edge" and was willing to make clear that "if Israel were to be attacked by any state, that we would stand by them".

Obama expressed concern about how the talks have strained US-Israel relations, indicating how he takes it personally when he's accused of being anti-Israel.

"Part of what has always made the US-Israeli relationship so special is that it has transcended party, and I think that has to be preserved. There has to be the ability for me to disagree with a policy on settlements, for example, without being viewed as ... opposing Israel."

Obama's comments came as Israeli Prime Minister Benjamin Netanyahu urged the US on Sunday to seek a better deal to curb Iran's nuclear programme and US Senate Republicans pressed their demand that the US Congress be allowed to vote on the agreement.

Netanyahu engages in US

Netanyahu has been strongly critical of the deal struck on Thursday in Switzerland, saying it threatens the survival of Israel. Netanyahu said he has spoken with both Democrats and Republicans in Congress - nearly two-thirds of House of Representatives members and a similar number in the US Senate - about the Iran nuclear issue.

In appearances on US television on Sunday, Netanyahu did not repeat his assertion on Friday that any final agreement should include a commitment by Iran recognising Israel's right to exist.

But, speaking on CNN's "State of the Union" programme, he said of the deal, "This is not a partisan issue. This is not solely an Israeli issue. This is a world issue because everyone is going to be threatened by the pre-eminent terrorist state of our time, keeping the infrastructure to produce not one nuclear bomb but many, many nuclear bombs down the line."

Source: Agencies