MADRID (AP) — Spanish authorities say a homemade submarine abandoned off the country’s northwest coast had 3 metric tons of cocaine on board.

National police and the finance ministry said in a statement Wednesday that it is the first-time drug smugglers have attempted to use a submarine in Europe.

They said using submarines to smuggle cocaine is “very common” in the United States.

An international operation involving police from Spain, Portugal, the U.S., the U.K. and Brazil tracked the fiberglass vessel across the Atlantic.

The submarine was due to pass the cocaine to another vessel, but the three people on board abandoned the submarine amid rough seas off Spain last Saturday night.

Two Ecuador nationals were arrested. A third is at large.

Authorities say the submarine could carry up to 5 metric tons.