Ecuador's coast guard says the country's marines have seized a semisubmersible capable of transporting 10 to 15 tons of cocaine. The vessel was under construction on a small island in the Gulf of Guayaquil.

The coast guard says in a statement that the vessel was 50 feet (15 meters) long and 13 feet (4 meters) wide and about 70 percent finished.

The state-run Andes news agency said the craft was similar to a semisubmersible seized Monday by Colombia off the neighboring country's southwest coast.

The craft discovered in Ecuador late Monday was the second semisubmersible found this year in the country.

Semisubmersibles move just below the water's surface, requiring air intake and exhaust pipes as they are powered by internal combustion engines.

They are widely used to smuggle cocaine to Mexico for transit to the United States.