(CNN) Authorities in the Spanish region of Galicia seized a semi-submersible submarine carrying more than 3,000 kilograms (6,614 pounds) of cocaine on Sunday.

The drugs are thought to have originated from Colombia but authorities are still investigating, according to a spokesman for the Civil Guard, a military agency with policing powers.

The vessel was seized Sunday off the coast of the port of Aldan. Two of the three crew members operating the 22 meter-long (72 feet) vessel were arrested.

Spanish authorities start operations to float a submarine containing 3,000 kilos of cocaine from the Aldan river estuary on the Galician coast in northwestern Spain, on November 25, 2019.

Both are Ecuadorian nationals, according to the Civil Guard spokesman, who said that authorities are looking for the third crew member.

"We are working on getting the submarine out of the water to check everything properly," he added.

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