Carlos Ivan Marquez, chief of Colombia's national office for disaster response, said the surviving Americans had injuries including multiple bone fractures and burns over at least 40 percent of their bodies.
The plane had been contracted by the U.S. government to provide detection and monitoring of drug trafficking routes in the coastal region of Central America, Southern Command said in a statement. It said the names of the dead are being withheld pending notification of next-of-kin.
"We express our sympathies to the families of the deceased, and are particularly saddened by the loss of a Panamanian Air National Guardsman,'' said Gen. John Kelly, commander of United States Southern Command. "We also want to thank the Colombians for their outstanding rescue and recovery efforts. The U.S., Panama, Colombia, and all of our partners in Operation Martillo remain committed to our longstanding cooperative relationship for counter-narcotics operations.''
Panama's National Air Service said in a statement that Panamanian officer Lt. Lloyd Nunez had died in the crash. It said the plane went down during an anti-drug operation along the border of the two countries and that Panama was assisting Colombia in the rescue operation.
Santiago Castro, director of Colombia's Civil Aviation agency, said the small plane wasn't civilian so he couldn't provide details about its route, origin or destination.
The region where the plane went down is mountain jungle and units of the Revolutionary Armed Forces of Colombia, or FARC, operate in it along with drug traffickers, the Colombian army said in a statement.
The statement from US Southern Command said there was no indication the plane was shot down.
- AP