Aides to U.S. President Donald Trump hired an Israeli private intelligence company to dig up dirt on officials serving in the administration of former U.S. President Barack Obama, who were involved in negotiating the 2015 Iran nuclear deal, according to documents obtained by Britain’s Observer newspaper and published in The Guardian.

According to the report, Trump staffers hired the company in May 2017 to find material to use against Ben Rhodes and Colin Kahl.

The investigators were reportedly instructed to probe Rhodes’ and Kahl’s private and public affairs to see if they had any links to lobbyists who were positively disposed towards Iran or were in a position to personally benefit from the nuclear deal.

In addition, investigators were instructed to investigate media personalities who had spoken out in favor of the deal in The New York Times, the MSNBC cable-news network and Israeli newspaper Haaretz.

The Guardian quoted former U.K. Foreign Secretary Jack Straw, who characterized the allegations as “extraordinary” and “appalling,” as saying that Trump and Israeli Prime Minister Benjamin Netanyahu were desperately trying to “discredit” officials involved in negotiating the agreement.

According to unnamed sources, U.S. officials with links to Trump reached out to the unnamed Israeli intelligence firm several days after Trump paid his first presidential visit to Israel last year. Trump made a promise to Netanyahu that Iran would not attain nuclear weapons and expressed his disdain for the 2015 agreement, which he has repeatedly castigated as the “worst deal ever.”

The Guardian report confirmed contact between the Trump aides and the intelligence company, but it is still unknown how much if any material was discovered and what use, if any, was made of it.

The White House declined to comment on the report.