MADRID (AP) — Spanish police have detained a fishing boat loaded with nearly three metric tons (3.3 short tons) of cocaine south of the Canary Islands, authorities said Sunday.

The police intercepted the 20-meter-long (65-foot-long) vessel called the AKT 1 on Wednesday around 300 nautical miles (555 kilometers) south of the Spanish archipelago located in the Atlantic Ocean off west Africa.

Police arrested the five crew members — four Turkish citizens and one person from the ex-Soviet republic of Georgia — on the ship that was smuggling the drugs in a fuel tank. The drugs were believed to come from an unspecified location in South America, police said.

A Spanish air patrol spotted the suspicious ship while it was trying to hide among a fleet of fishing vessels. It was then boarded by a customs patrol boat.

Police said that they are focusing on cracking down on what they call the “African route” for South American traffickers who transfer loads of drugs to fishing vessels in the middle of the Atlantic before smuggling them into Europe.