We've got dope in the water!"

Kevin Stanfill, the top U.S. Drug Enforcement Administration agent in the Bahamas, snapped shut his cell phone. An Army Blackhawk helicopter pilot had just reported a possible air drop of five large drug bundles in the water 30 miles south of Nassau — about an hour from "Hawk's Nest," a U.S. antidrug installation on this island in the central Bahamas.

The DEA quickly got its own chopper into the air while the Royal Bahamas police launched a speedboat to check out a suspicious vessel near the possible drop zone. U.S. Coast Guard and Army helicopters circled the target area, waiting for the police boat to arrive.

Within minutes, the 43-foot Bahamian police boat roared up at 50 mph. Two officers boarded the boat and a diver plunged into the shark-infested sea.

The possible drugs, it turned out, were actually large squares of sheet metal used by some fishermen to lure lobsters. The suspect boat was innocent after all.

But the recent episode witnessed by an Associated Press reporter and photographers who accompanied DEA agents on patrol demonstrated the challenges faced by U.S. and Bahamian officials, who are battling drug traffickers in a 700-chain of islands as large as the state of California.

The two governments, along with officials from the Turks and Caicos islands to the south, have collaborated since 1982 in a joint operation credited with driving many cocaine and marijuana smugglers toward Mexico's border with the United States.

The Caribbean has long been a paradise for smugglers who take advantage of the many islands, crowded waters and weak law enforcement in countries such as Haiti. The DEA has estimated that as much as 20 percent of the cocaine that reaches the United States moves through the Caribbean, although that figure has varied over time.

"We've been successful here," said Stanfill. "We always want to maintain that presence."

It is often difficult to quantify whether the United States is gaining ground in the long, costly war on illicit drugs.

Despite hundreds of arrests and billions of U.S. dollars spent, cocaine continues to be "widely available throughout the nation," the DEA said in a 2006 drug threat assessment. Yet there are some success stories and the DEA points to the Bahamas as one of them.

Since 2000, Operation Bahamas and Turks and Caicos has resulted in seizure of more than 25 tons of cocaine, nearly 82 tons of marijuana and the arrests of 786 people, according to the DEA. The operation costs the U.S. government about $30 million a year.

With its hundreds of tiny islands and cays, a vast expanse of water and prime location as close as 45 miles east of Florida's coast, the Bahamas has long been a haven for pirates and smugglers of every stripe.

During the drug traffickers' 1980s heyday, airplanes laden with cocaine regularly took off for the United States from clandestine airstrips in the Bahamas. Boats carried drug loads every day — some of them blending into the legitimate maritime traffic, others speeding toward the coast under cover of night.

Although the United States hasn't proposed pulling out of the joint operation, Bahamian officials fear that if Washington were to turn attention elsewhere it would jeopardize hard-won progress. The amount of cocaine that is smuggled through the Bahamas has dropped from about 80 percent of the drugs that reached the United States 20 years ago to about 10 percent today.

"We have to be cognizant of the open corridors we have here in the Bahamas," said Bahamas Drug Enforcement Unit Inspector Samuel Butler. "We have actually been able to hold the tide. If we do not have these assets in place, certainly the drug enterprises will be back in the Bahamas."

Mark Trouville, special agent in charge of DEA's Miami office, said U.S. officials fear that increased law enforcement efforts along the Mexico-U.S. border could raise the costs of smuggling drugs in the Southwest. That in turn could make the Caribbean and the Bahamas attractive again to the drug cartels.

"One of the reasons we stay vigilant is that these folks are nothing if not innovative, and they respond to pressure," Trouville said. "As more of our resources are going to the Mexican border, these folks will look at the original route and start to come back this way."

The smugglers use a network of caves in a part of the Bahamas known as the Raggeds to store drugs, sometimes marking their loads with brightly colored children's toys. Traffickers' planes regularly ditch in the ocean or crash on an island — finding wreckage is common — and speedboats are often run aground deliberately while being chased so smugglers can escape on foot.

These losses are all figured into the drug traffickers' costs of doing business, said DEA's Stanfill. It's an acceptable cost as long as cocaine that runs $2,000 a kilogram in Colombia retails for $20,000 in Miami.