Guatemala's navy captured a makeshift submarine loaded with five tonnes of cocaine bound for the United States, the Guatemalan military said on Sunday, according to Reuters. The navy, which was working with the U.S. Drug Enforcement Administration on the operation, stopped the 55-foot (17-meter) vessel on Friday off Guatemala's Pacific coast and arrested four Colombian men on board. "There was a sleeping compartment, another (compartment) for the engine, and a third for cargo which was full of cocaine," armed forces spokesman Byron Gutierrez told a news conference. The four men were taken into custody by DEA agents. Drug cartels ship hundreds of tonnes of cocaine from Latin America to the United States every year. In October 2009, a similar submersible was found 108 miles (175 km) off the Guatemalan coast, packed with 10 tonnes of cocaine. The steel-and-fiberglass vessels run partially submerged in an attempt to evade radar, but traffickers are working on more sophisticated designs. Ecuadorean authorities recently discovered a nearly-finished craft that would have been the first drug smuggling submarine to travel completely under the water.