The crackdown by the military against militants in Nigeria's oil-rich Niger Delta region is one of the reasons for record high oil prices as companies reduce staff in the oil fields. Multi-national companies have started reducing production in the volatile area.
So far, Nigeria's top oil producing company, Royal Dutch/Shell, is losing an estimated 40,000 barrels a day because of fighting in the Niger Delta region. This is just a sliver of Nigeria's approximate 2.3 million barrels a day output, but production could go down further, if waterways become more dangerous.
Nigerian government forces started bombing militant bases in creeks around Port Harcourt last week, using fighter jets and helicopter gunships, while raiding communities looking for militants. This led the Anglo-Dutch company to evacuate 235 non-essential staff from two oil fields.
A leader of the militants, Mujahid Dokubo-Asari, responded, saying he would launch an uprising across the entire oil-producing region. He says his ethnic Ijaw movement, called the Niger Delta People's Volunteer Force, has more than 150,000 members.
Mr. Asari says his fighters will soon start attacking oil installations of the Italian oil company, AGIP, which operates four main onshore blocks, accusing it of lending helicopters to the military. The company denies this.
A Nigerian analyst, Layi Abegurin, says many Nigerians are sympathetic to the militants' claims for more local access to oil revenues.
"It's the responsibility of multinational oil companies and Nigerian leadership," he said. "The Nigerian leadership, politicians, they are corrupt, they have collaborated with big oil companies in exploiting the people of Niger Delta. Can you believe the Niger Delta is the breadbasket of Nigeria to produce the oil, but they are the worst area of Nigeria?"
Government officials who say corruption is being tackled efficiently, accuse the militants of being gangsters fighting for smuggling routes used by oil thieves. Oil companies also deny the accusations of corruption, and say they hire local workers, while funding community projects.
Last year, a violent uprising by members of the Ijaw tribe, who are a majority in the Delta, forced companies to briefly shut 40 percent of Nigeria's output.