A two-year-long drug investigation has reached a preliminary peak after Spanish police has discovered no less than 4.5 tonnes of cocaine hidden in an animal feed container aboard a Togolese cattle ship.

The freighter was en route from South America to the Middle East carrying livestock when raided in a coordinated effort off the island of Gran Canaria, report news agencies Reuters and AFP.

According to Spanish police, the ship has been monitored for two years due to suspicions of having been used for narcotics transportation.

Previously, neither Spanish police nor other authorities had been able to find any illegal drugs aboard the carrier.

According to a police statement cited by Reuters, international drug smugglers are finding new ways to operate, using livestock freighters, for instance, as conditions for concealing illicit cargoes are particularly favorable.

The 4.5 tonnes of cocaine, having an estimated market value of EUR 105, were seized as part of coordinated efforts between Spanish police, the US Drug Enforcement Administration and Togo police.

There were 28 persons employed on the ship. They are all under arrest.

The incident marks the second time in January that Spanish police seize a major cocaine cargo aboard a merchant ship off the Gran Canaria.

Previously this month, vessel Blume was raided off the Spanish holiday island, with police discovering a similar amount of illegal drugs.

English edit: Kristoffer Grønbæk