ABUJA — Five Indian sailors kidnapped when their ship was attacked off the coast of Nigeria last month have been released, the vessel's operating company said on Saturday. Pirates looted the SP Brussels, an oil and chemicals tanker, on Dec. 17 about 40 miles (65 km) off the coast of the Niger Delta, a vast wetlands region home to Africa's largest energy industry. “Five crew members who were taken from the vessel by armed men ... have been released,” Medallion Marine said in a statement. “All five are reported to be in good health after their ordeal.” There were no details on how they were freed but in the past ransoms have been paid. The Nigerian navy had no immediate comment. Piracy and kidnapping in Nigeria's oil-producing Delta and offshore are common. The Gulf of Guinea is second only to the waters off Somalia for the risk of pirate attacks, which drives up shipping and oil industry costs. Nigeria is a busy oil shipping route. The West African country is among the world's top 10 crude oil exporters and imports around 80 percent of the fuel products needed for its 160 million people due to a lack of domestic refining capacity.— Reuters