Defending the program at a meeting in Dublin, Ireland, Holder said the leaks also had harmed America's allies, CNN reported Friday.
"The national security of the United States has been damaged as a result of those leaks," he said. "The safety of the American people and the safety of people who reside in allied nations have been put at risk as a result of these leaks."
European Commission Vice President Viviane Reding told Holder the European Union has "serious concerns" about the surveillance program, which has allowed the National Security Agency to collect data about phone calls made and received by Americans.
German Chancellor Angela Merkel said in Berlin Friday she intends to discuss with U.S. President Obama on the need for transparency in the PRISM surveillance program, a secret program used to gather information from the Internet.
On the telephone surveillance program, Holder said courts allowed the information to be collected only if there was "reasonable suspicion" the calls were related to terrorist activity.
Holder did not mention the name of Edward Snowden, the former NSA contractor who claims to have revealed information about the agency's efforts in collecting telephone data. However, the attorney general told the group, "I'm confident the person who is responsible will be held accountable."
Snowden is believed to be in Hong Kong, but a representative of Singapore Airlines said Friday the British Home Office had urged the airline not to allow Snowden to board a flight for the United Kingdom.
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