Gunmen have kidnapped an Egyptian oil services worker from a Nigerian vessel contracted by Italian energy firm Agip off the coast of the Niger Delta, the company which owns the vessel said on Friday

A spokesperson for Tethys Plantgeria Ltd, a Nigerian firm which provides technical services for offshore oil development projects, confirmed Thursday's abduction but declined to give any further details.

Security sources said the ship, named Melody and contracted by the Nigerian Agip Oil Company (NAOC), was attacked by robbers on Thursday afternoon.

Militant gangs using speedboats have a history of attacks on oil rigs and ships operating off the coast of Africa's biggest crude exporter. Hostages have usually been released after payment of a ransom.