The Nigerian military has denied a claim it fired indiscriminately at civilians during a hostage rescue attempt in the Niger Delta.
The military attacked three villages in Rivers State on Friday.
But the military said the operation was to break up a militant camp in the area, not to rescue two British oil workers kidnapped last September.
Militants said the attack had caused civilian casualties, but that could not be confirmed.
“In a rather crude and bizarre approach for that sort of rescue attempt, they began firing from the air, land and sea at defenceless and innocent civilians who had no idea why they were being attacked,” the Movement for the Emancipation of the Niger Delta (Mend) said in an e-mail to journalists.
But the military said the statement was “Mend propaganda”.
They said the operation was to destroy the hideout of a gang thought to be responsible for kidnapping oil workers and extortion.
A military spokesman said there had been no casualties and no arrests.
“We wouldn’t want to risk the lives of the hostages,” Lt Col Sagir Musa said.
“We know how to do those kind of operations. Do they think we are so unprofessional as to open fire from afar?”
Mend said the villages were not militant hideouts, and said the hostages had been moved deeper into the creeks and mangrove swamps of the Niger Delta as a precaution.
Restrictions placed on journalists by the military mean it is very difficult to get out into the creeks of the Niger Delta to confirm either side’s claims.
On Saturday a group of gunmen reported to be “affiliates” of Mend, hijacked a tug boat belonging to an oil services company, taking its eight crew hostage.
They used the tug to attack an oil tanker off the coast of the Niger Delta.
The crew of the tanker, belonging to Royal Dutch Shell, locked themselves in the hold while the militants ransacked the vessel.
They threatened to blow up the ship, before leaving with some stolen equipment, according to a Shell security briefing seen by the BBC.
Other unconfirmed reports had said one man had been killed in the attack.
The tugboat was later found adrift, the location and nationality of the crew are unknown.
Mend says it is fighting for a fairer distribution of wealth from Nigeria’s oil, but there are many armed groups in the Delta who make money out of extortion, kidnapping and oil theft under the direction of powerful and well connected political figures.
Britain has promised military training to help the government combat the problem.
Mend says it will not release the British hostages until the British withdraw and a leader currently being tried in secret is released.