Several people were killed as an oil flow station operated by Royal Dutch Shell in southern Nigeria was attacked by unidentified ethnic militants on Sunday, while four oil workers abducted four days ago were still being held by the kidnappers.

"Heavily armed persons ... attacked the SPDC (Shell's subsidiary in Nigeria) Benisede flow station in Bayelsa State," said a Shell statement. "The attackers invaded the flow station in speed boats, burnt down two staff accommodation blocks, damaged the processing facilities and left."

The statement said Shell had commenced evacuation of personnel on duty from Benisede, and neighboring flow stations while a Shell spokesman in Lagos said some people were injured as soldiers there exchanged fire with the invaders.

"Some people were injured during the attack. I don't have the number, but we have moved to (the oil city of) Warri for medical attention," the spokesman told Xinhua. "The Benisede flow station (attacked) has been shut since January 11," he added.

The Benisede flow station was one of the four facilities closed on Wednesday after local militants vandalized a major pipeline feeding the Forcados terminal. The attack forced Shell to cut production of 106,000 barrels of oil per day, or five percent of Nigeria's total output.

A local journalist in Warri however told Xinhua that there were casualties on both sides during the fight between the soldiers and invaders on Sunday morning. "Several people were killed, but nobody has the exact number," she quoted military sources as saying.

The attack came four days after armed men, riding in three boats, stormed Shell's EA oil field offshore Nigeria's southern coast, taking hostage four workers, a Briton, an American, a Bulgarian and a Honduran who were working for the firm's two subcontractors, Tidex and Ecodrill.

The four were still being held by the alleged kidnappers belonging to a previously unknown group, who calls itself the Movement for the Emancipation of the Niger Delta.

The group said that they were not out for cash ransom but to bring the issues of resource control in the impoverished delta, where the majority of Nigeria's oil is produced, to the front burner.

The group also demanded the release of Diepreye Alamieyeseigha, former governor of Bayelsa state who was impeached and arrested in December for money laundering, and Mujahid Dokubo-Asari, a local ethnic militia leader who faces treason charges.

"We are capable and determined to destroy the ability of Nigeria to export oil or other petroleum products for that matter," the group said in a statement to the media.

"For the safety of its citizens, the United States and other European nations with citizens on our soil will do well to advise these individuals to leave immediately."

Nigeria is the biggest oil producer in Africa with a daily output of 2.5 million barrels, while Shell accounts for half of the country's oil production.

(Xinhua News Agency January 16, 2006)