A Liberia-flagged oil tanker has gone missing off the coast of Ghana and a senior port official told Reuters on Saturday the captain sent a distress call to say the vessel was attacked by pirates.

The Liberia-flagged MT Fair Artemis last made contact with its manager, Fairdeal Group S.A., at 6 p.m. (1800 GMT) on Wednesday when it was operating off the coast of Ghana, the company said. The ship failed to make contact the next day.

Pirate attacks jumped by a third off the coast of West Africa last year, pushing up insurance costs for shipping firms operating in a key commodities export hub.

“Our primary concern … is for the safety of those on board the vessel. We would like to assure their families and all stakeholders that we are fully committed to returning the crew and vessel to a safe port,” said Fairdeal fleet director John Gray in a statement.

A spokesperson for the company said on Saturday the ship remained missing but gave no further details.

A senior official at the port in Tema, east of Ghana’s capital, told Reuters: “We had a distress call from the master of the ship yesterday (Friday) saying he was 36 nautical miles away from our waters after he was hijacked and looted in Togolese waters early Wednesday.”

The official declined to be identified.

West African piracy has its roots in an uprising in Nigeria’s oil-rich Niger Delta that has given rise to criminal networks. Gangs target cargo, which is often fuel, and rob or kidnap crew members.

The gangs threaten oil security in the Gulf of Guinea beyond Nigeria including in Ghana and Ivory Coast, where offshore discoveries have sparked interest from international oil firms and prompted efforts to turn the zone into an oil and gas hub. [ID:nL6N0BIAJ5]

There are signs the pirates are growing more daring as they attacked a tanker in January off the coast of Angola and sailed it to the Nigerian coast in what was the most southerly attack on record.

A spokesman for Ghana’s armed forces said the Navy were on the lookout for the vessel, which was built in 2009.