The SH-60B Seahawk helicopter went down early Tuesday while flying within sight of the frigate USS DeWert, which was their floating base, said Bill Austin, a spokesman for the U.S. Naval Station at Mayport, Florida, where the troops had their homeport.
"The helicopter didn't transmit any kind of distress call that we know of," said Austin. "There were three crew members on board, and the helicopter was conducting scheduled flight operations."
The search ended Tuesday night, and crew members' names were being withheld pending notification of their families, the Navy said in a statement.
The frigate is part of a unit that usually carries out anti-drug missions in international waters, and the Navy said the helicopter crew was "conducting counter-narco terrorism operations" at the time of the crash.
The U.S. has been helping the Colombian police and military battle the country's drug gangs and have made several major arrests in recent years. The Pacific coast of Colombia is a popular haven for drug smugglers, with the lands penetrated by few roads and bisected by inland waterways.
Drug traffickers in this area typically pack several tons of cocaine onto speed boats sometimes equipped with global positioning systems and satellite telephones, and then dart toward Mexico and Central America, where the drugs are taken across land to the United States.
The boats have been known to have custom-made 800-horsepower fiberglass boats that can go up to 50 mph.
Since the year 2000, the United States has spent $4 billion for "Plan Colombia," a joint U.S.-Colombia anti-drug program. The United States has provided the Colombian government with military training, equipment and other aid under the project.
U.S.-made helicopter crashes in Colombia generally have involved U.S.-donated helicopters flown by Colombian troops on military missions. Since 1999, six U.S.-made Black Hawks have crashed in Colombia, killing at least 67 Colombian soldiers and injuring 37.