Captain Sinefi Hungiapuko said the navy would try to retake the platforms without violence. According to e-mail messages sent from the rigs by foreign staff, the Nigerian strikers have threatened to resist.

"The navy is directly involved now," he said. "We are trying to make sure things are settled peacefully. The navy is in the area. Our men will move to take control of the rigs ... immediately."

Asked what the navy would do if it encountered resistance, Hungiapuko asked simply: "What action would you expect military men to take?"

Nigerian workers on four US-owned oil platforms lying in the Gulf of Guinea in deep water south of the Niger Delta launched a protest on April 19 after four union colleagues were sacked for alleged theft.

They have blocked the helicopter landing decks and restricted access to the rigs from the sea, despite an appeal from their union to back down.

According to the British foreign ministry there are 97 expatriate staff on board the four rigs, including 35 Britons.

Other diplomatic sources in Nigeria said that 21 US citizens were on board, along with an unknown number of French and other European nationals.

Although some foreign oil workers have been allowed to leave for personal and medical reasons during the protest, most remain trapped in increasingly stressful conditions.

E-mail messages from the hostages, released Tuesday, warned that the strikers have threatened to blow up the rigs and kill everyone on board if Transocean Inc, Inc, the Houston-based owners of the rigs, attempts to take them back by force.

Industry and diplomatic sources in Nigeria have played down such threats, however, refusing to describe the trapped oilmen as hostages.

In Lagos the Nigerian oil workers' union, the National Union of Petroleum and Natural Gas workers (NUPENG), was meeting with Transocean to try to find a way out of the crisis.

NUPENG general secretary Joseph Akinlaja told AFP: "We are hopeful that the crisis will be amicably resolved at today's meeting."

The US firm has won a court injunction ordering the strikers off the platforms and has retained four bailiffs, each accompanied by three armed police officers, to enforce the order.

NUPENG has already disowned the "wildcat strike" and has called on its members to back down. But it could still go back to the 100 protesters if Wednesday's meeting produces an improved management offer.

As he arrived at the talks, the union's deputy secretary general Elijah Okougbo said: "We are trying to negotiate between the workers on the rigs and the management of the company..

He denied that the foreign workers were in danger.

"They are safe, it is an industrial matter. Nobody is being held hostage," he told reporters.

The workers are believed to be seeking severance payments in exchange for quitting the four platforms, the Sedco 709, the MG Hulme, the Trident 8 and the Trident 6, which Transocean operates off the Niger Delta.

Three of the platforms are leased by the Anglo-Dutch oil group Shell.

A Shell spokesman told AFP on Wednesday that some of its expatriate employees were among the trapped workers, but that it was not involved in the talks except in an advisory role.

Transocean staff in Nigeria refused to comment on the crisis.

Nigerian oil facilities are often taken over by strikers or by local militants keen to extract lucrative concessions from the wealthy foreign companies that produce the country's sole profitable export.

It is rare for expatriate staff to be hurt in these incidents.

Last month violent unrest in the western Niger Delta forced three oil multinationals to suspend their operations, stopping more than 40 percent of Nigeria's daily exports of crude.

Nigeria is the world's sixth largest oil exporter, with an OPEC quota of more than two million barrels per day.

SPACE.WIRE