Panamanian authorities say they have seized 6 tons (5.5 metric tons) of cocaine on three boats off a Pacific island.

Prosecutor Edwin Guardia says it is the biggest drug seizure this year in Panama. The country is a key transit point for drug trafficking from Colombia to the United States and Europe.

Security forces found the cocaine in 273 packets Monday on board three boats off Coiba island. Police were searching for 15 people who escaped the raid.

Guardia said Wednesday the cocaine was believed to be worth $137 million.