MIAMI (CBSMiami) – The deadly crash of a DH-8 aircraft that was monitoring coastal drug trafficking lanes in the Western Caribbean is being investigated by U.S. authorities.

Four of the plane’s six crew members were killed, but rescue crews managed to locate two survivors.

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The crash happened near the Colombia-Panama border just before 2 a.m., Saturday. The DH-8 aircraft was in support of Operation Martillo according to a press release by Doral based U.S. Southern Command (SOUTHCOM).

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The names of the deceased are not being released pending notification of next-of-kin.

Operation Martillo (Hammer) is a U.S., European, and Western Hemisphere effort to target illicit trafficking routes in coastal waters along the Central American isthmus.  The U.S. military participation is led by Joint Interagency Task Force South which is a component of SOUTHCOM.

Fourteen countries participate in Operation Martillo: Belize, Canada, Colombia, Costa Rica, El Salvador, France, Guatemala, Honduras, the Netherlands, Nicaragua, Panama, Spain, United Kingdom and the United States.  Chile has also contributed.

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The efforts coordinated through Joint Interagency Task Force South resulted in the disruption of 152 metric tons of cocaine and 21 metric tons of marijuana before it could reach the United States in 2012. The drugs have a wholesale value of $3 billion according to U.S. officials.