ABUJA Nigeria's main militant group said Monday it had sabotaged a Chevron oil facility and seized a chemical tanker and six crew members, the latest in a string of attacks in Africa's biggest energy producer.
The Movement for the Emancipation of the Niger Delta (MEND) said it attacked Chevron's Okan manifold late Sunday in the southern Delta state, hours after it sabotaged an oil well head operated by Royal Dutch Shell.
It was not immediately possible to independently verify the statement.
U.S. oil firm Chevron, which halted swamp operations in Delta state following attacks on its pipelines in May, said it was investigating the report.
Chevron, Shell and Italian energy firm Agip have cut output by around 273,000 barrels per day in the last six weeks following the latest campaign of militant violence.
The disruption to supplies have helped support global oil prices in the past few weeks. But prices fell Monday to $64 a barrel as traders focused on the global economic recovery.
MEND also said Monday it seized a chemical tanker and six crew members off the coast of Escravos in the Niger Delta. It said three of the hostages were from Russia, two from the Philippines and one from India.
"Six crew members from the chemical tanker Siehem Peace was seized about 20 nautical miles from Escravos Sunday ... and will be held until further notice," said MEND, who threatened further offshore attacks.
The military could not immediately confirm the report.
Militants have launched at least four attacks against the oil industry in Nigeria in the last 10 days, dashing hopes that an amnesty offer by President Umaru Yar'Adua would buy a period of calm.
Yar'Adua said on June 25 he would offer a 60-day amnesty to gunmen to try to end unrest which has prevented Nigeria from pumping above two-thirds of its installed capacity since early 2006, costing it billions of dollars in lost revenue.
Some militant leaders have indicated they would be willing to accept the offer, provided they can negotiate the terms. But MEND, a loose network of various armed factions, has doubted the government's sincerity.
The militant group has called for the release of its leader Henry Okah, who is on trial for gun-running and treason and could face the death penalty. MEND says Okah needs urgent medical attention for a kidney ailment.
Yar'Adua last week ordered his interior minister to extend the clemency offer to Okah, but he has so far failed publicly to do so and Okah's trial continued last week.
"The government should display the highest form of integrity and sincerity over the detention of Henry Okah at this period of his fading health," MEND said.
(Editing by Jon Boyle)