A report from a defunct Justice Department agency exaggerated when it claimed Mexican drug cartels were operating in more than 1,000 U.S. cities, The Washington Post reported Monday.

The Philadelphia-based National Drug Intelligence Center, or NDIC, distributed the report in 2011.

The number of American cities where Mexican cartels supposedly operated "is misleading at best," the Post said, citing interviews with U.S. law enforcement officials and drug policy analysts.

"They said the number is inflated because it relied heavily on self-reporting by law enforcement agencies, not on documented criminal cases involving Mexican drug-trafficking organizations and cartels," the Post said.

The newspaper said it interviewed police officials in more than a dozen cities.

The officials "said they were surprised to learn that the federal government had documented cartel-related activity in their communities," the Post said.

The Drug Enforcement Administration, or DEA, which absorbed NDIC's personnel last year, refused to release a list of the cities, describing the information as "law enforcement sensitive," the newspaper said.

"Privately, DEA and Justice Department officials said they have no confidence in the accuracy of the list," the Post said.

The Post said it was able to identify more than one-third of the cities using computer mapping techniques and government documents.

"The analysis located government claims of Mexican drug activity in numerous cities in unexpected places: 20 in Montana, 25 in Oregon, 25 in Idaho, 30 in Arkansas," the newspaper said.

"There is no disputing that Mexican cartels are operating in the United States," the Post said. "Drug policy analysts estimate that about 90 percent of the cocaine, heroin, marijuana and methamphetamine on U.S. streets came here courtesy of the cartels and their distribution networks in Mexico and along the Southwestern border."

Numerous cases of cartel activity in Houston, Los Angeles, Chicago and Atlanta have been documented, DEA officials told the newspaper.

"But analysts who study drug trafficking scoffed at the contention that the violent cartels and other Mexican-based drug organizations are operating in more than 1,000 U.S. cities," the Post said. EFE