Nigerian authorities are continuing efforts to free the four foreign oil workers kidnapped earlier this week in the country's oil-rich Niger Delta.
A spokesman for Bayelsa state, where the kidnappings took place, says officials are trying to contact the group that is believed to have abducted the oil workers.
The spokesman says the hostages are alive.
The kidnappers, members of a previously unknown militant group, have demanded the release of a former provincial governor arrested on corruption charges, and the leader of another Niger Delta guerrilla group.
The four oil workers - an American, a Briton, a Bulgarian and a Honduran - were kidnapped Wednesday from an oil platform run by the Royal Dutch Shell company. Nigerian authorities say they have located a boat carrying the workers and their captors off the country's southern coast.
Some information for this report was provided by AFP and Reuters.