U.S. lawmakers were unable to tell targets about the hacking because information was so secret, Reuters reports, citing three unidentified people familiar. Leaders briefed last summer included Republicans Senate Majority Leader Mitch McConnell, Speaker of the House Paul Ryan, Senator Richard Burr and House Rep Devin Nunes; Democrats included were Senator Harry Reid, House Rep Nancy Pelosi, Senator Dianne Feinstein, House Rep Adam Schiff NSA, other intelligence agencies sometimes delay informing
Source: Bloomberg Politics