A U.S. observation plane spotted a suspicious boat Sunday night and caused it to head to Costa Rica.
At the same time, the Servicio Nacional de Guardacostas sent out two craft and the Servicio de Vigilancia Aérea put an aircraft in the sky.
The suspicious craft landed at Punta Mona de Gandoca in Manzanillo on the southern Caribbean coast, and the two occupants fled into the jungle.
Security officials said that the craft was being inspected for traces of drugs as were two packages that the crew threw into the ocean. There also were signs that the craft was carrying containers of fuel.