'Attack' mars Nigeria oil amnesty
Militant attacks have sharply cut Nigeria's oil output
Nigeria's main oil militant group has claimed to have carried out a new attack in the Niger Delta, hours after the president offered an amnesty.
Mend says it attacked an oil field run by Royal Dutch Shell, following a military raid on a village. Neither claim has been independently verified.
The group's acting leader told the BBC that amnesties were only for convicted criminals but said he did want peace.
"General" Boyloaf said Mend would disarm if a militant leader was freed.
Henry Okah is facing trial on charges of gun-running after being arrested in Angola last year.
"General" Boyloaf said the group would keep "not even a bullet" if Mr Okah was freed within a week, under the terms of the president's offer.
"We really appreciate the announcement but we reject amnesty," he told the BBC's Network Africa programme.
"But we accept peace. We are not criminals. We are ready to work hand-in-hand to make sure there is development in the region."
However, his group, the Movement for the Emancipation of the Niger Delta (Mend), has claimed to have attacked the offshore Royal Dutch Shell-owned Afremo field in Delta State.
Mend says this was in response to a "punitive expedition" to capture suspected militants in Agbeti village.
The military denied carrying out any attack, reports Reuters news agency.
On Thursday, President Umaru Yar'Adua unveiled details of a 60-day amnesty for militants in the Niger Delta.
Ministers of Nigeria's Council of State have approved the proposal - an effort to end years of attacks on the region's beleaguered oil industry.
A presidential pardon, rehabilitation programme, education and training are being offered to militants taking part.
"I hereby grant amnesty and unconditional pardon to all persons who have directly or indirectly participated in the commission of offences associated with militant activities in the Niger Delta," Mr Yar'Adua said.
The grace period will end on 4 October, he added.
Mend also claimed to have carried out an attack on Wednesday, as Russian President Dmitry Medvedev signed investment deals worth billions of dollars with President Yar'Adua.
Militant attacks in the region have reduced oil production to 1.3m barrels per day, officials say.
Nigeria's Opec quota is 2m.
The militants claim they are fighting for the rights of local people to benefit more from their region's oil wealth.
But many attacks in the lawless region are undertaken for financial gain.