The comments came as Israel pushed its case to have the deal changed or eliminated, arguing intelligence documents it recently unveiled on Iran's alleged nuclear ambitions helped demonstrate why.

Some experts believe Trump will pull out of the agreement concluded in 2015 under his predecessor Barack Obama, and which he has harshly criticised.

They have also questioned whether Israeli Prime Minister Benjamin Netanyahu's televised unveiling of the trove of tens of thousands of intelligence documents on April 30 was coordinated with Washington.

"In effect, I don't know what Trump will decide because he hasn't told me," the senior Israeli official said on condition of anonymity, making clear Israel had not yet been informed of Trump's decision.

The official added however that "I think that he has the same sceptical view."

Proponents of the nuclear deal argued the trove of documents Israel obtained from Tehran shed little new light on Iran's nuclear programme and in fact made the case for why the accord is important.

Netanyahu argues the documents show the deal with his country's main enemy was built on a lie -- Iran denied having pursued nuclear weapons -- and demonstrates it has a secret atomic weapons programme ready to activate at any time.

World powers that were party to the agreement, including Britain and France, said those arguments only strengthened the reasoning for the deal, which has safeguards in place designed to keep Iran from pursuing nuclear weapons.

They also said the intelligence documents, obtained in February, did not show Iran was violating the deal.

Trump could decide by May 12 to reimpose US sanctions on Iran, which had been lifted as part of the agreement.

The Israeli official said that while he did not know what action Trump would take, there could be a range of options.

He said he believed Trump could decline to renew a waiver on sanctions but use the lag time before they took effect to re-negotiate from a stronger position.

The US president could alternatively single out firms key to Iran's economy in order to apply pressure on Tehran.

- 'Dangerous deal' -

Netanyahu on Sunday disputed arguments that the intelligence trove he unveiled contained no new details.

He also said it did not matter if Iran violated the agreement or not, since the deal was fatally flawed.

"If you don't violate a dangerous deal, it doesn't make it less dangerous," said Netanyahu, whose country is believed to be the Middle East's sole nuclear power, though it has never acknowledged it.

A senior Israeli intelligence official said the vast majority of the documents uncovered were not previously known.

Trump and his Middle East allies, particularly Israel, argue the agreement was too weak and must be replaced with a more permanent arrangement and supplemented by controls on Iran's missile programme.

Restrictions on Iran's nuclear activities begin expiring in 2025.

Netanyahu has also said lifting sanctions has increased Iran's ability to finance proxy militants.

Beyond that, there have been tensions between Israel and Iran in Syria, where Tehran is backing Bashar al-Assad's regime.

Israel has pledged not to allow Iran to entrench itself militarily in the neighbouring country.

It has been accused of carrying out deadly strikes there, most recently on April 9 and April 30, which killed Iranian forces as well as Syrian soldiers.

"We are determined to block Iran's aggression against us even if this means a struggle," Netanyahu said Sunday.

"Better now than later... We do not want escalation, but we are prepared for any scenario."