The FBI is intensifying the hunt.
Director Robert Mueller said the agency is stepping up efforts to arrest the defense contractor responsible for leaking information about the federal government’s sweeping surveillance programs, Reuters reports.
Mueller, who confirmed an investigation is underway, said the leak damaged U.S. national security.
“We are taking all necessary steps to hold the person responsible for these disclosures,” Mueller told the House of Representatives Judiciary Committee. “These disclosures have caused significant harm to our nation and to our safety,” he said.
Edward Snowden, a defense contractor, has acknowledged being the source of the NSA leaks.