"According to the Post account, in January 1997, the National Security Agency (NSA) had intercepted a phone conversation between an Israeli official at the embassy in Washington, and Danny Yatom, the head of the Mossad, Israel's foreign intelligence service. The official sought permission from the spy boss to "go to Mega" in order to obtain a copy of a confidential letter that had been sent by then-U.S. Secretary of State Warren Christopher to Palestinian Authority President Yasser Arafat, concerning U.S. assurances about a recently negotiated agreement for an Israeli military withdrawal from the Hebron area in the West Bank. Yatom, according to the NSA intercept, rejected the request, admonishing his agent, "This is not something we use Mega for."
The idea that the Israeli government was running another spy operation inside the U.S. national security establishment created a tremendous stir. The Washington Post, in its May 7, 1997 leak, had reported, "One official with knowledge of the FBI investigation into the identity of Mega cautioned that much remained unknown. But the official said that if it turned out that a senior U.S. official was passing sensitive information to Israeli authorities, it could prove more serious than the espionage case involving Jonathan Jay Pollard, a former Navy analyst who was convicted in 1986 of selling U.S. military intelligence documents to Israel."
https://larouchepub.com/other/2001/2833mega_spy.html