The U.S. started keeping from 1992 records of international phone calls made by Americans, under a joint program of the Department of Justice and the Drug Enforcement Administration, according to a newspaper report.
The secret program, which aimed to counter drug trafficking, collected logs of "virtually all telephone calls" from the U.S. to as many as 116 countries linked to drug trafficking, according to USA Today, which quoted current and former officials associated with the operation. But the content of the calls was not recorded as part of the collection.
The existence of the program was disclosed in January by a DEA official in testimony to a federal court, but the details were sketchy.
The program preceded the bulk phone records collection by the National Security Agency in the country's fight against terrorism, which came into sharp focus in June 2013 after disclosures by the agency's former contractor Edward Snowden that the NSA was collecting call metadata, which does not include content, from telecommunications companies.
The DEA got hold of the records using administrative subpoenas that allowed it to collect records "relevant or material to" federal drug investigations, according to USA Today. Some telecommunications companies were hesitant to provide the information in such volumes, but the subpoenas were not challenged in court. Those companies that were reluctant received letters from the DOJ asking them to comply.
DEA did not use the information collected as evidence in court for prosecutions or for seeking warrants so as to keep the program secret, but tip-offs were given based on the data to field agents.
The countries that were targeted changed over time, but included Canada, Mexico and most of Central and South America. Besides targeting drug cartels, the records were also used to rule out foreign involvement in the 1995 bombing of a federal building in Oklahoma City, besides identifying U.S. suspects in other investigations.
The bulk data collection halted in September 2013 after the storm over Snowden's various revelations about NSA surveillance.
The drug agency now sends the telecom operators daily subpoenas for international calling records involving only phone numbers that agents suspect are linked to the drug trade or other crimes, adding up to sometimes a thousand or more numbers a day, the newspaper said quoting unnamed former and current officials.
The agencies could not be immediately reached for comment. A DOJ spokesman Patrick Rodenbush told USA Today that the DEA "is no longer collecting bulk telephony metadata from U.S. service providers."
A DEA assistant special agent testified in a federal court in January that the agency had queried an Iranian number in a federal law enforcement database in connection with a federal criminal investigation.
The database consisted of telecommunications metadata collected from U.S. telecommunications companies, agent Robert Patterson told the U.S. District Court for the District of Columbia. Use of the database was suspended in September 2013, he added.