“This is like an avalanche. It is very detrimental and, candidly, I found it very concerning,” Feinstein said. “There’s no question that this kind of thing hurts our country.”

The FBI opened its own probe Tuesday into who disclosed information on the Iranian attack, The Wall Street Journal reported. On Capitol Hill, the Senate Armed Service Committee promised hearings, while two Republican senators called for a special counsel investigation.

Several Democrats noted with alarm that the Iranian cyber leak is just the latest in a series of media reports that disclosed classified information about U.S. anti-terrorism activity.