PARIS -- Pirates seized a ship belonging to French maritime services company Bourbon off the coast of Nigeria during the weekend and are holding nine crew members hostage, the company said Monday.

"Bourbon confirms that the Bourbon Leda and its nine crew members (five Nigerians, two Ghanaians, one Cameroonian and one Indonesian) were seized off the coast of Nigeria during the night of Saturday January 3 to Sunday January 4," a statement said.

"Bourbon received Sunday, January 4, a call which allowed it to be in contact with the commander of the Bourbon Leda who confirmed that all crew members were safe and in good health."

The Bourbon Leda, a vessel of the FSIV (Fast Supply Intervention Vessel) type was attacked off Bonny, a major oil and gas terminal in southern Nigeria. At the end of October another vessel belonging to Bourbon, which specializes in offshore oil activities, was seized by pirates off the Nigerian coast.

On August 2, two French crew members of a Bourbon supply ship were kidnapped by armed men in a bar in the port of Onne, near Port Harcourt, Nigeria's oil capital. They were freed in September.

The Niger Delta has seen with increasing regularity since 2006 acts of violence by armed groups which have kidnapped oil sector workers, attacked installations and carried out acts of sabotage.

Nigeria is one of sub-Saharan Africa's two biggest oil producers.