Attackers carrying assault rifles and rocket-propelled grenades stormed a transport vessel carrying oil workers off the southern coast of Nigeria, kidnapping four Americans late Tuesday. Gilbert da Costa reports for VOA from Abuja on the escalating violence in the oil-rich territory.

More than 30 foreigners have been kidnapped in the Niger Delta since the start of the month, a dramatic upsurge in attacks on oil facilities and workers so far this year.

Most of those seized have been released.

The wetland region's high-profile armed group, the Movement for the Emancipation of the Niger Delta, attacked three oil pipelines Tuesday in a renewed campaign to cripple the Nigerian oil industry.

Ibiba Don Pedro, a newspaper editor in the main oil city of Port Harcourt where most of the current violence had been centered, says the petroleum-producing territory is fast slipping into anarchy.

"We are moving, firmly, firmly, beginning from Rivers state, in the direction of Somalia, where you have warlords controlling sections of Rivers state," said Pedro. "That is where we are going, I can tell you that with everything I have observed. Perhaps in the next two, three years it is going to blow out and we are going to have a totally lawless. Rivers state - the capital of the oil industry in the country."

Rich in oil reserves, the Niger Delta has long become a battleground for militants who claim to be fighting for a larger share of the country's oil wealth for local people and armed gangs out to make ransom money.

Pedro draws a correlation between recent elections and the spiraling violence, noting that politicians have long armed groups in the region.

"It is just a confused mess really, much of what is happening. You have militants who were helping the PDP [ruling Peoples' Democratic Party] carry ballot boxes, intimidate people in Okrika, in Port Harcourt," added Pedro. "They were at the center of the bombing of police stations and all of that. I learned that authoritatively only few days ago."

The kidnapped Americans were part of a group of workers laying pipelines for U.S. contractor Global Industries, working for oil giant Chevron at its Okan oilfield in Southern Nigeria.

Thousands of foreign oil workers have been evacuated from Nigeria because of militant attacks since February 2006.