A report released on Tuesday revealed that several years before the National Security Agency began recording Americans’ phone calls, the Drug Enforcement Administration had its own program that began recording calls in 1992.

The report, which was first released by USA Today, found that the DEA’s operation began in 1992, acted as a blueprint for the NSA’s massive data collection program, and was the government’s “first known effort to gather data on Americans in bulk, sweeping up records of telephone calls made by millions of U.S. citizens regardless of whether they were suspected of a crime.”

As previously reported, the existence of the DEA’s program was first revealed in January. However, the full scope of the program was not exposed at the time. USA Today noted that while its report gives insight into the program, there are parts of it that still remain classified.

Officials involved with the operation told USA Today that for more than two decades, the Justice Department and the DEA “amassed logs of virtually all telephone calls from the USA to as many as 116 countries linked to drug trafficking,” with target countries including Canada, Mexico and most of Central and South America.

In a letter from the Justice Department to Sprint in 1998, obtained by USA Today, the department asked the phone company to turn over its call records, and called the DEA’s data collection “one of the most important and effective Federal drug law enforcement initiatives,” which had been “approved at the highest levels of Federal law enforcement authority,” according to Mary Lee Warren, the head of the department’s Narcotics and Dangerous Drugs Section.

According to the report, DEA agents did not intercept the content of the phone calls, but they did obtain which numbers were called and when, and they then linked those numbers to an electronic collection of investigative reports, domestic call records and foreign intelligence data.

USA Today reported that although the NSA’s program is still in place, Attorney General Eric Holder halted the DEA’s program in Sept. 2013, after Edward Snowden revealed that the NSA was collecting call records and data from innocent Americans. The report claims that the DEA now sends subpoenas to phone companies, in order to obtain international calling records, and that they sometimes request “a thousand or more numbers a day.”