Israeli spies were warned by their American counterparts not to share intelligence with the Trump administration until they could be sure he hadn't been compromised by Russia.

American intelligence officials recently shared their concerns about Donald Trump and his transition team's ties to Russia, which is working with Iran on the side of the Assad regime in Syria, reported the Israeli newspaper Yedioth Ahronoth.

“The Israelis who attended the meeting said that the Americans advised them not to expose any sensitive sources to members of the Trump administration, lest that information reach Iranian hands, until it becomes clear that Trump does not have a compromised relationship with Russia and is not vulnerable to extortion,” reported investigative journalist Ronen Bergman.

The date of the meeting was not revealed to protect the newspaper's sources, although it was described as recent.

The American officials told the Israelis that the National Security Agency (NSA) had “highly credible information” that Russia’s intelligence agencies were responsible for hacking the Democratic National Committee during the election and shared the stolen data with WikiLeaks to hurt Hillary Clinton.

They told the Israelis that Russia President Vladimir Putin had "levers of pressure" over Trump but did not offer any details.

The newspaper reported that the potential leverage may include allegations made in a dossier compiled by a former British spy that was known to U.S. intelligence agencies for months but published this week online.

American and Israeli intelligence have conducted joint operations against Iran, as well as Hezbollah and Hamas, although President Barack Obama ended offensive activity against Iran after secret talks began in 2013 over a nuclear agreement.

The newspaper reported that American officials believe Edward Snowden exchanged sensitive information about operations in Iran for political asylum in Russia, which U.S. believes then shared the intelligence with Iran.

"Parts of it were handed over to Tehran as part of Putin’s policy to increase Iranian dependence – not just Syrian dependence – on Moscow, all aimed at serving one final purpose: To restore Russia’s position as the influential world power in the region," the newspaper reported.

Trump has denounced reporting on the dossier as "fake news."