A submarine carrying three tons of cocaine has been discovered near the Galapagos Islands by naval authorities, the Ecuadorian interior minister says.

Jose Serrano said on Friday that three crew members were arrested after their vessel suffered mechanical problems near the maritime boundary with Colombia.

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Anti-narcotics agents from both Ecuador and Colombia pursued the craft, which was described as a handcrafted semi-submersible.

Colombia’s navy was reported as saying that local authorities had aerial assistance from the US government. The shipment was presumed to be destined for the US market.

In September, officials captured a similar submarine near the coast of both countries.