The operation in Colombia's southwest allegedly was run by the paramilitary Black Eagles, the Los Angeles Times reported Saturday.
The newspaper noted the laboratory was located in a coastal zone that has become a battleground for drug traffickers, right-wing militias and leftist rebels.
The laboratory reportedly was raided by the "Junglas" special anti-drugs force, using Black Hawk and Huey helicopters.
The Times said police found 4 tons of refined cocaine, and an additional 1.7 tons of cocaine base, which is convertible to more than 1 ton of pure cocaine.
The lab complex had its own power plant and housed 50 workers. The facility was capable of producing an estimated 5 tons of pure cocaine a week, authorities said.