WASHINGTON – Aides of U.S. President Donald Trump used the services of a private Israeli intelligence firm to "get dirt" on former Obama administration officials who were involved in crafting the 2015 Iran nuclear deal, according to a report published Saturday by the British newspaper The Observer.

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Trump's aides reportedly contacted the Israeli investigators just days after the U.S. president's May 2017 visit to Israel, where he promised Prime Minister Benjamin Netanyahu that Iran would never possess nuclear weapons.

Open gallery view Obama with Ben Rhodes, Deputy National Security Adviser for Strategic Communications, in the Oval Office, September 10, 2014. Credit: Pete Souza \\ The White House

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The report said the investigators specifically looked for information about Ben Rhodes, former U.S. President Barack Obama's deputy national security adviser for communications.

The point of what The Observer describes as "the dirty campaign" was "that people acting for Trump would discredit those who were pivotal in selling the deal, making it easier to pull out of it," the report quoted a source with details of the operation as saying.

"The Trump camp" reportedly also asked the Israeli firm to contact journalists in leading media outlets covering the Iran deal and obtain information from them about potential leaks from Rhodes and other Obama officials – leaks that supposedly would have violated national security procedures. One of the news outlets mentioned in the Guardian report is Haaretz.

The report noted that while "sources have confirmed that contact and an initial plan of attack was provided to private investigators by representatives of Trump, it is not clear how much work was actually undertaken, for how long or what became of any material unearthed."

The report said that the White House offered "no comment" when contacted. The Observer is the Sunday version of the British newspaper The Guardian.

Trump is expected to announce by May 12 whether he will recertify the Iran accord, which he has called "the worst deal ever." He has declared that he will withdraw from the agreement unless changes are made, such as limitations on Iran's ballistic missile program.

A presentation by Netanyahu on Monday about what he said was documentary evidence of Tehran's past nuclear arms program could give Trump a fresh argument to withdraw, even though United Nations inspectors say Iran has complied with the terms of the deal.

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Earlier Saturday, the Boston Globe reported that former U.S. Secretary of State John Kerry met with Iranian Foreign Minister Mohammed Javad Zarif at the UN headquarters in New York two weeks ago in an attempt to save the deal. Kerry reportedly also met with German President Frank-Walter Steinmeier and French President Emmanuel Macron and spoke on the phone with EU foreign policy chief Federica Mogherini.

Kerry was instrumental in formulating the deal with Iran, seen as one of his main achievements as secretary of state, a post he left more than a year ago.