Armed men have seized a Nigerian tanker carrying 5,000 tons of jet fuel in the Ivory Coast port of Abidjan, officials say.
Authorities first reported the hijacking of the vessel, with 16 Nigerian crew members on board, on Monday. The ITRI was seized as it was preparing to deposit the fuel at the port, according to a statement from the Ivory Coast's government.
Port officials said the tanker's last known position was off the coast of neighbouring Ghana, but Ghanaian authorities said they had been unable to locate the ITRI.
Shipowner Brila Energy, a petroleum distributor based in Nigeria, said it was monitoring the situation.
"The vessel is still missing and the hijackers whose sole objective is to steal the cargo of Jet A1 on board the vessel are yet to make any demands," Chairman Rowaye Jubril told The Associated Press.
Noel Choong, head of the International Maritime Bureau's pirate reporting centre in Malaysia, said in many previous cases, the pirates released the crew after they had syphoned out the oil and obtained any valuable cargo.
The ship initially had trouble docking because a sand storm reduced visibility, a government statement said. Later, the ship's captain radioed the port manager to report difficulty manoeuvring.
Shortly afterwards, contact was lost with the vessel. Then ship consignee Koda Maritime informed port officials that armed men had taken control of the tanker.
Most hijackings in the region occur near oil-rich Nigeria, but analysts say co-ordinated efforts by authorities and neighbouring countries have forced Nigerian pirates to seek easier targets outside their home waters.
"Nigeria and Benin have had joint actions for two years, and they have been quite successful. We haven't seen the kinds of heavy attacks that we used to see," said Martin Ewi, a senior researcher with South Africa's Institute for Security Studies.
"Ivory Coast seems to be attracting those that have been driven out."
The first recorded vessel hijacking off Ivory Coast was in October, when 14 men armed with knives and AK-47s boarded a tanker carrying 30,000 tons of petrol. The tanker was released three days later in Nigerian waters with the crew unharmed, but the pirates allegedly made off with about 2,500 tons.