Top US spy blasts phone surveillance leak AMERICA'S top spy chief James Clapper warns that leaks of secret court documents about a scheme to capture millions of phone records risked US national security. In a statement on Thursday, Clapper, the Director of National Intelligence, said "the unauthorised disclosure of a top secret US court document threatens potentially long-lasting and irreversible harm to our ability to identify and respond to the many threats facing our nation." Clapper's intervention came as controversy swirled over a National Security Agency scheme to sweep up millions of telephone records in a program designed to find suspicious patterns of activity that could tip off US authorities to terror attacks. The program does not involve the "tapping" of phones but instead collects data to be analysed in mathematical programs. Clapper said a newspaper article in The Guardian that discussed the program, based on a secret court document ordering phone provider Verizon to turn over records, was "misleading." "The article omits key information regarding how a classified intelligence collection program is used to prevent terrorist attacks and the numerous safeguards that protect privacy and civil liberties," Clapper wrote. Clapper said he had ordered the declassification of certain information about the program so Americans could understand the limits of its use. He said a "robust" legal regime was in place to govern the practice under the Foreign Intelligence Surveillance Act (FISA) and said the collecting of telephone records was authorised by Congress.