The Nigerian army has killed at least eight militants in the oil-producing Niger Delta region, sources say.
Nigerian militants have been responsible for kidnappings
The militants were stopped as they travelled in a boat. Weapons and ammunition were found before the men were shot, they say.
The killings come at a sensitive time, after militants called a month-long truce to give the new government the chance to hold talks.
Attacks in the Niger Delta have led to a 25% cut in Nigeria's oil output.
The BBC's Abdullahi Kaura in the Niger Delta says it is not clear if those killed belonged to the main militant group, the Movement for the Emancipation of the Niger Delta (Mend).
He says the killings in Bayelsa State could jeopardise the recent truce.
Mend has freed several foreign hostages it had seized as part of its campaign for more oil wealth to be used to help local people.
Nigeria is Africa's biggest oil producer but most of its people live in poverty.
President Umaru Yar'Adua has pledged to address chronic underdevelopment in the Niger Delta, which is home to Nigeria's multi-billion dollar oil industry, producing 90% of the country's export earnings.