WARRI, Nigeria, 3 March 2006 — World oil prices surged yesterday as Nigerian officials stepped up efforts to free US and British hostages and head off further rebel assaults on production facilities in the Niger Delta. Africa’s largest oil producer has already lost around 20 percent of its output following a series of attacks by separatist guerrillas on and around the energy giant Shell’s Forcados export terminal in the western delta.

Last month, Shell evacuated staff from the region and halted exports totaling 455,000 barrels per day. Several pipelines have been blown up. On Wednesday, the US major Chevron said it had shut down the nearby Makaraba oil flow station, cutting off a further 13,000 barrels per day, after a crude pipeline sprang an unexplained leak. At the same time, the rebels threatened more attacks.

“The concern right now is Nigeria, with the Chevron incident,” said Tony Nunan, a Tokyo-based energy analyst, as the price of Nigeria’s sweet light crude jumped 77 cents to $62.74 per barrel in electronic trading.

Meanwhile, Nigeria’s Power Ministry said attacks on two gas pipelines last week had cut supplies to two power stations, cutting the country’s domestic electricity output by around a quarter and threatening increased blackouts. Insurgent fighters from the self-styled Movement for the Emancipation of the Niger Delta (MEND) released six hostages oil workers on Wednesday, after holding them for 13 days in the delta swamps.

But three foreigners - US oil workers Cody Oswald and Russel Spell and British security expert John Hudspith - are still being held at a rebel base around 40 kilometers (25 miles) west of the oil city of Warri. In a statement e-mailed to the media, the militant group vowed to “commence with attacks in another area of the Niger Delta with an aim to ensuring the total discontinuation of export of onshore crude oil.”

A spokesman for Delta State’s Governor James Ibori, who is leading efforts to negotiate with the hostage-takers, said that a former militant leader now working for the government had set off into the swamps to meet them. “We’re stepping up negotiation with their captors so that they can be off the hook imminently,” said the spokesman, Abel Oshevire. “We are aware of the psychological trauma the remaining three will be going through now. Before, there were nine and after the release the remaining three must definitely be depressed,” he said.

“We’re going to make sure that their depression ends soon,” he promised.

For their part, MEND insisted that the hostages’ release was not the result of any deal with Ibori’s negotiating team. The group said Macon Hawkins, a 69-year-old Texan, had been released as a humanitarian gesture because he suffers from diabetes.

And the Egyptian, Thai and Filipino hostages are free because their countries have no interests in the Nigerian oil sector, it said. The gang say they are fighting to win the delta’s 14 million ethnic Ijaws a greater share in the region’s oil revenues and have demanded that Shell pay $1.5 billion in damages to polluted villages.