WARRI, Nigeria -- Ethnic militants on Saturday threatened to blow up 11 multinational oil installations they claimed to have captured in retaliation for government military raids.

Dan Ekpebide, a leader of Ijaw tribal fighters in Nigeria's oil-rich Niger Delta, said his followers took over oil pipeline facilities belonging to ChevronTexaco, Royal/Dutch Shell and TotalFinaElf on Friday. The companies had earlier evacuated the sites during unrest that has killed scores of people.

The threats came as the army accused the tribal fighters of attacking a TotalFinaElf facility on Saturday morning. Two Nigerian army soldiers and a retired officer guarding the facility were among five people killed, army spokesman Col. Chukwuemeka Onwuamaegbu said.

Ijaw militants said 65 of their ranks died in battles with government troops on Friday and Saturday.

The fighters demanded that the Nigerian military halt raids carried out almost daily against their villages. They also insisted that the government redraw voting boundaries ahead of April elections.

The Ijaws, with 8 million people the largest ethnic group in the delta, have long accused President Olusegun Obasanjo of colluding with minority Itsekiris to draw up unfavorable voting boundaries ahead of April elections.

"We'll blow up these flow stations and blast the pipelines. We will take Nigeria 20 years backward," Ekpebide told The Associated Press, without giving details. Witnesses say the fighters are armed with machine guns and grenades.

Six of the captured facilities belong to Shell's Nigerian subsidiary. ChevronTexaco has three and the other two belong to TotalFinaElf.

The facilities pipe crude oil to the companies' individual export terminals.

A TotalFinaElf spokesman, speaking on condition of anonymity, confirmed the capture of its facilities. Spokesmen for ChevronTexaco and Shell said they could not confirm the attacks because their staff had been evacuated.

However, other witnesses, including leaders of the Ijaws' main ethnic rivals, the Itsekiris, confirmed the Ijaws had captured all 11 facilities.

The fighting has cut multinational oil exports by 350,000 barrels a day -- about one-sixth of Nigeria's total production of two million barrels a day. Nigeria is the fifth largest supplier to the United States.

The military insists it has used minimum force. Hundreds of heavily armed soldiers have been deployed to the delta, reinforcing 10,000 troops based there.

"We've been very restrained," army spokesman Onwuamaegbu said. "We don't know how long our patience will last."