Negotiations to free eight foreign workers abducted from an oil rig in the Niger Delta are progressing well, government officials have said.
Numerous armed militia groups operate in the Niger Delta
President Olusegun Obasanjo has joined in the mediation efforts and his spokeswoman said he was optimistic the men would be freed unharmed.
Six Britons, a Canadian and an American were seized on Friday from an offshore rig in the south of the country.
Militants in the region are seeking more local control of oil wealth.
The BBC's Alex Last in Lagos said indications are that negotiations with the kidnappers should be resolved quickly.
The men are reported to be in good health - they have received clothing and toiletries and have also been allowed to call their employers.
It is not clear who is holding the men.
The rig, 20km (12miles) out to sea, had sent out a distress call on Friday, saying it was under attack from between 20 and 30 men in speedboats.
The attackers in four boats fired shots into the air before boarding the rig, security sources said.
There were 84 oil workers on the rig when it was attacked, said a spokeswoman for Aberdeen-based Dolphin Drilling, which operates the rig.
The Nigerian government said the kidnapping appeared to be the result of a local dispute.
In the Niger Delta that usually means a community feels it has not been sufficiently compensated by oil companies and in those cases often a cash payment resolves the issue, our correspondent says.
An upsurge of attacks on foreign oil interests has cut Nigeria's oil production by 25% - a key factor in the high world price of crude oil.
The Niger Delta is home to Nigeria's oil industry, but there is widespread poverty and numerous armed militia groups operate in the area.
One group, the Movement for the Emancipation of the Niger Delta (Mend), says it is fighting for greater local control of the oil revenues and compensation from oil companies for pollution in the Delta.
In recent months, Mend has twice taken foreigners hostage in a series of raids. In both cases the men were eventually released unharmed.
However, the group has sent an email to media organisations saying it was not involved in Friday's kidnappings.
In April, Mend rejected President Obasanjo's offer of thousands more jobs and a new motorway for the area, saying it did not address its demands for more local control of oil wealth and demilitarisation.