FBI Director Robert Mueller appeared before a US House Judiciary Committee on June 14, after a whistle-blower claimed that the National Security Agency, (NSA), secretly monitored Americans’ telephone and email communications.
Mueller told the committee: “These disclosures have caused significant harm to our nation and to our safety. We are taking all necessary steps to hold the person responsible for these disclosures.”
NSA contractor Edward Snowden has admitted leaking the classified information to Britain’s Guardian newspaper and the Washington Post in America.
Snowden said he made the disclosures because he believed some of the NSA’s measures were intrusive and illegal, a claim Washington denies.
The FBI said the surveillance programs had been useful in foiling plots that could have threatened the country’s security.