Israeli intelligence officials are concerned that the exposure of classified information to their American counterparts under a Trump administration could lead to their being leaked to Russia and onward to Iran, investigative journalist Ronen Bergman reported by Israeli daily Yediot Ahronot on Thursday.

The intelligence concerns, which have been discussed in closed forums recently, are based on suspicions of unreported ties between President-elect Donald Trump, or his associates, and the government of Vladimir Putin in Moscow.

As Russian intelligence is associated with intelligence officials in Tehran, highly classified information, such as Israel’s clandestine methods of operation and intelligence sources, could potentially reach Iran. Such information has been shared with the United States in the past.

American intelligence officials expressed despair at the election of Trump during a recent meeting with their Israeli counterparts, Bergman reported. They said that they believed that Putin had “leverages of pressure” over Trump, though they did not elaborate. The American media reported on Wednesday that Russia has embarrassing intelligence about the president-elect.

According to Bergman, the American intelligence officials implied that Israel should “be careful” when transferring intelligence information to the White House and the National Security Council (NSC) following Trump’s inauguration – at least until it is clear that Trump does not have inappropriate connections with Russia.

Cooperation between the Israeli and U.S. intelligence communities has intensified over the past two decades, with most of the joint operations directed, according to reports, against Iran. Hezbollah and Hamas were also intelligence targets. An official agreement in 2008 for comprehensive cooperation, including the exposure of sources and methods of action, reportedly led to impressive results, including the disruption of the Iranian nuclear program.