Nigeria's leading militant group is threatening to launch a wide-scale offensive off the coast of the oil-rich Niger Delta against oil platforms, a move that would escalate the already intensified attacks against foreign petroleum installations in the region.

The Movement for the Emancipation of the Niger Delta in recent days has stepped up its campaign of violence against oil and gas operations, leaving by some estimates more than 100 people dead, according to local news reports.

So far, the violence -- though targeting foreign companies has claimed the lives of locals in the delta -- has been isolated to Rivers State, home to the region's de facto capital, Port Harcourt.

However, that could change, MEND said in a statement sent to media Wednesday, saying "the hurricane will be heading to the neighboring states in the Niger Delta" in the coming days.

One of the primary targets of recent MEND attacks has been operations run by Royal Dutch Shell, the country's leading foreign oil operator.

Earlier this week, MEND, along with another militant group from the delta, attacked a Shell flow station and one of its shared pipelines.

Shell has been the primary target of militant hostilities since the latest waves of militancy swept through the delta at the end of 2005, causing billions of dollars in lost revenue and prompting some companies to pull up stakes.

In July bombings at Shell installations and pipelines prompted the company to declare a force majeure on exports from those pipelines.

At the beginning of this year Shell shut down operations at its Forcados terminal following pipeline attacks that threw its 100,000 barrel-per-day production offline. The terminal already had been shut once before because of violence and reopened in October 2007 after more than a year of halted production. Since its reopening, the facility, which can produce some 450,000 barrels per day, had been operating at a fraction of its capacity.

In July 2007 a leading Nigerian activist group called on Shell to shut one of its pipelines, saying the company has done little to control the fires that burned for several weeks.

"I think this is yet another indicator why there is greater need for transparency in the oil sector," said Emira Woods, co-director of Foreign Policy in Focus at the Institute of Policy Studies, who also expressed skepticism about the validity of the report.

For Nigeria's armed groups, Shell appears to represent the totality of their ire for the petroleum industry and its effects on the vastly poor populace of the delta.

Since the 1970s Nigeria has pumped more than $300 billion worth of crude from the southern delta states, according to estimates, though most residents live on less than $1 a day.

High unemployment in the delta, environmental degradation due to oil and gas extraction, and a lack of basic resources such as fresh water and electricity have angered some of the region's youth and incited them to take up arms, forming militant groups such as MEND.

The increased violence has caused Nigerian oil output to decline by 650,000 barrels per day, the West African country's vice president noted last month.

The recent spike in clashes between militants and Nigerian soldiers and private security has cost the country about 115,000 barrels per day in output, said Nigerian energy officials.