Police say kidnappers have released 14 Nigerian oil workers and their driver unharmed more than two weeks after they were abducted. They would not say if ransoms were paid.

The employees of oil industry service company Nestoil were abducted by gunmen on Sept. 2 near Nigeria's southern oil capital, Port Harcourt.

Police Deputy Superintendent Nnamdi Omoni said they were rescued in batches starting Saturday and ending Sunday evening.

The kidnappers had demanded a ransom of 100 million naira, which is about $322,600.

Kidnappings of Nigerians and foreigners are common all over the country. In the oil-rich southern Niger Delta, they are carried out by ordinary criminals as well as militants demanding a greater share of oil riches for locals.

Hostages are usually released unharmed after ransom payments.