Declan McCullagh/CNET

U.S. law enforcement officials working on counter-narcotics operations have had routine access to AT&T's enormous database of Americans' phone records dating back more than 25 years, according to a New York Times report.

The Hemisphere Project involves a close relationship in which the government has paid company employees to supply drug-enforcement officials with phone data dating back as far as 1987, the Times reported. The partnership, which began in 2007, is reportedly similar but separate from the National Security Agency's controversial data-collection programs revealed earlier this year.

However, unlike the NSA's collection of phone logs, the data covered by Hemisphere is stored by the company with access granted via administrative subpoena. The database, which includes records on every call that passes through the company's network, not just AT&T customers, grows by 4 billion records a day.

Details of the program were revealed in a 27-slide PowerPoint presentation provided to the newspaper by peace activist Drew Hendricks, who received the information in response to public information requests. The slides were marked "law enforcement sensitive" and indicate that the program was to be carried out in great secrecy.

"All requestors are instructed to never refer to Hemisphere in any official document," one slide states.

The Obama administration acknowledged and defended the use of the database but said the program represented no privacy risk.

"Subpoenaing drug dealers' phone records is a bread-and-butter tactic in the course of criminal investigations," Justice Department spokesperson Brian Fallon told the Times. The program "simply streamlines the process of serving the subpoena to the phone company so law enforcement can quickly keep up with drug dealers when they switch phone numbers to try to avoid detection," he said.

AT&T told CNET that it could not comment on the report but indicated it was bound by government requests for data.

"While we cannot comment on any particular matter, we, like all other companies, must respond to valid subpoenas issued by law enforcement," an AT&T spokesperson said in a statement.