Pirates have attacked an oil tanker off the coast of west Africa, killing a Ukrainian seaman, the commander of Benin's naval forces says.

Cdr Fernand Maxime Ahoyo says the Cancale Star's chief engineer was killed and one other crewman wounded.

The pirates attacked the vessel some 18 nautical miles (33km) off the coast of Benin, in what correspondents say is the country's first such attack.

One pirate was overpowered by the crew, but the others managed to escape.

Benin-based journalist Esther Tola told the BBC that the pirates were thought to be from Nigeria.

The commander said naval forces had rescued the crew from the tanker and brought them into port.

There were 24 seamen of different nationalities on board the Liberia-flagged vessel, including Filipinos, Lithuanians and Ukranians, Cdr Ahoyo told AFP news agency.

Western front

The International Maritime Bureau (IMB) says piracy in the waters of west Africa is on the rise, with 100 such incidents recorded last year.

The IMB has previously warned of heightened piracy risks along shipping routes in Nigeria and Ghana, to the east and west of Benin.

It said attacks usually took place while ships were at anchor or close to coastal areas, unlike in eastern Africa, where Somali pirates strike ships hundreds of miles out to sea.

More than 10 ships and 200 hostages are currently being held by pirates operating in waters off Somalia.

An international force of about 40 warships has been stationed around the Gulf of Aden, in an effort to clamp down on piracy in some the world's busiest shipping lanes.