Cartels are contracting a growing group of middle men to process the paste into cocaine in Bolivia, saving time they would otherwise spend processing it themselves, Bolivia's anti-drug police chief Oscar Nina told The Associated Press Thursday in an interview.

"There is more interest and investment in purifying coca paste here and exporting it, rather than sending it to Colombia for purification" as in years past, Nina said.

Police have raided three modern cocaine labs in Bolivia's eastern lowlands in recent months, arresting two Colombians at one jungle factory that was discovered when police intercepted a small plane carrying 660 pounds (300 kilograms) of cocaine in March.

While no Colombians were found at the other two labs, there were signs of a Colombian presence, Nina said, giving few other details.

The shift mirrors a pattern seen in Peru in the mid-1990s, when anti-drug police say local groups began making cocaine from coca they'd previously sent to Colombia for processing.

Bolivian coca is largely harvested by local families. Some crush its leaves into paste and sell to intermediaries from Colombia, Peru, Brazil and Bolivia, Nina said.

Those middle men then process the paste into cocaine at labs across eastern Bolivia, and fly it out from hidden jungle airstrips or have so-called human mules carry it into Brazil and Peru on foot, Nina said.

Bolivian police say they busted 3,000 such labs last year, seizing a record 27 tons of cocaine from largely small operations. So far this year, they report seizing 9 tons of cocaine and making 992 drug-related arrests.

Bolivia is the third largest producer of coca and cocaine after Colombia and Peru.

Much Bolivian coca is legally grown for use in teas and herbal remedies in the country's central Chapare region, where President Evo Morales began his political career as head of a coca-growers union.

Morales acknowledged for the first time last December that some Bolivian coca ends up as cocaine, blaming "drug addiction" in foreign countries for the shift. But he also said he considers drug trafficking a betrayal of Bolivia and warned coca producers he would send state security forces to the region if they participated in the drug trade.

A gram of cocaine may sell for about $2 in Bolivia, but more than $100 in the U.S.