ABIDJAN, Ivory Coast — A French tanker seized by pirates off Ivory Coast and its crew of 17 sailors have been released, its owner said Wednesday, though two workers suffered injuries in the hijacking. SEA Tankers, a shipping firm based in Merignac, France, issued a statement saying the M/T Gascogne is now under the control of its crew and is traveling safely away. The company did not say the ship's location, nor did it describe how the ship was freed. A spokeswoman also declined to offer further details. The two injured sailors are receiving medical care, SEA Tankers said. The ship was hijacked by pirates Sunday off Abidjan, the largest city in Ivory Coast. Government officials there had said the crew included seven sailors from Togo, four from Benin, two from Ivory Coast, two from Senegal and one apiece from China and South Korea. The company had been working for a South Korean firm at the time of the attack, according to Ivory Coast's Transportation Ministry. The attack Sunday comes amid a series of escalating assaults in the Gulf of Guinea, which follows the African continent's southward curve from Liberia to Gabon. Piracy in the Gulf of Guinea has escalated from low-level armed robberies to hijackings and cargo thefts. Last year, London-based Lloyd's Market Association — an umbrella group of insurers — listed Nigeria, neighboring Benin and nearby waters in the same risk category as Somalia, where two decades of war and anarchy allowed piracy to flourish. But as piracy has dropped in recent months off Somalia's coast, it's only risen in the Gulf of Guinea. However, attacks as far west as Ivory Coast are a new development. There have been two other similar hijackings off Abidjan since October. Pirates in West Africa have been more willing to use violence in their robberies, as they target the cargo, not the crew for ransom as is the case off Somalia. Experts say many of the pirates come from Nigeria, where corrupt law enforcement allows criminality to thrive and there's a bustling black market for stolen crude oil. Officials in Ivory Coast said owners of the M/T Gascogne received information Monday suggesting pirates had already sailed the hijacked tanker into Nigerian waters to steal its remaining fuel. In other cases, the crew has been set free after such fuel drops. — AP