Drug traffickers are using a fleet of as many as 20 mini subs to move huge quantities of cocaine through the Caribbean, federal law enforcement and Coast Guard officials tell ABC News. The cocaine vessels are often harder to detect than Russian submarines because of the way they skim the surface, officials say. "The Russian submarine has a certain signal you can listen to underwater," said Coast Guard Adm. Joseph L. Nimmich, director of Joint Interagency Task Force South, based in Key West, Fla. Photos: Drug Cartels’ Secret Weapon The cocaine vessels give "very little signal," said the admiral, whose officers are testing a captured sub in order to adjust Coast Guard sensors. In a report to be aired on "World News With Charles Gibson," officials showed off the recently captured vessel, a semi-submersible that carried 9,000 pounds of pure cocaine. "They started out with four to five tons. The new ones are estimated to carry between 12 to 15 tons of narcotics," Adm. Nimmich said. The vessels are able to travel up to 2,000 miles and evade U.S. Navy and Coast Guard ships patrolling the waters between Colombia and the U.S. and Mexico. U.S. officials say the cocaine trafficking groups actually assemble the vessels in the jungles of Colombia and then truck them to remote ports to be launched. The vessels carry a crew of only two or three and often are purposefully sunk if detected by patrol boats, officials say. The use of the subs comes as U.S. officials say cocaine prices have risen an estimated 45 percent in the last 10 months, a sustained trend that suggests supply is being affected. "Never happened before in, I think, 30 years of looking at the drug problem in the United States," said White House drug czar John Walters. "If we reduce the quality and raise the price, this product, like every other product, is susceptible to a declining market," Walters says. Critics say there have been other "blips" in cocaine prices before and that those have proven to be only temporary. "The price of cocaine today, even after this blip, is about 40 percent of what it was in the 1980s," said Ethan Nadelmann, the executive director of the Drug Policy Alliance, an organization that promotes alternatives to the war on drugs. "The drug czar is grasping for straws. Cocaine seems to be just as widely available on the streets as it ever was," said Nadelmann. Do you have a tip for Brian Ross and the Investigative Team?