Armed men have hijacked a tanker carrying 5,000 tons of oil from a port in Ivory Coast.

Ivorian port officials said Monday that the Nigerian-owned vessel, along with its 16 crew members, was seized late last week as it was preparing to unload at the port in Abidjan, the country's commercial capital.

The statement says officials believe the ship is currently located off the coast of neighboring Ghana. However, that has not been confirmed.

Hijackings and attacks on ships have increased along Africa's Gulf of Guinea in the past year.

The International Maritime Agency says piracy in West Africa, particularly in the Gulf of Guinea, is on the rise with 58 incidents reported in 2012, including 10 hijackings and 207 crew members taken hostage.

A total of five incidents were reported off Ivory Coast in 2012, up from one the previous year. In October, suspected Nigerian pirates seized a tanker carrying more than 30,000 tons of gasoline off the coast of Abidjan, the first reported hijacking in the country.