The head of Nigeria's House of Representatives has warned that spiraling violence in the oil-rich Niger Delta is now a major national security threat. The warning came hours after gunmen abducted eight oil workers in three separate incidents on Friday. The most prominent armed group in the region has vowed new attacks to prove it did not receive protection money from the government. Gilbert da Costa has more from Abuja for VOA.

A Nigerian separatist militant levels his machine gun at reporters from his war boat on the Escravos River in southern Nigeria (File)

Nigeria, the world's eighth largest oil exporter, is already suffering huge losses because of violence in the oil producing region.

Friday's attacks were the latest in the Niger Delta, the home of Africa 's biggest oil industry, which has become notorious for kidnappings and raids on oil sites since militants launched a campaign of sabotage two year ago.

Thousands of foreign workers have left since 2006 as violence has spiraled, and some industry executives see the situation descending further into anarchy.

Nigeria's parliament Speaker Dimeji Bankole says the crisis is out of control and requires external intervention.

 "If care is not taken, it will begin to move out of the Niger Delta and consume the whole nation," he said. "And it is not rocket science to figure that out. This is no longer a Niger Delta problem, nor a Nigerian problem but a global problem."

More than 200 foreigners have been seized in the Niger Delta since early 2006. Almost all have been released unharmed. Armed men kidnapped two Germans working for a construction firm near Port Harcourt, the main city in the Niger Delta, two weeks ago.

Several foreign firms, including French tire company Michelin and oil servicing firm Wilbros, have left the region because of security problems.

Relations and friends of prominent Nigerians have also been targeted by gangs seeking ransom money.

Violence in the Delta, a wetlands region, is rooted in poverty, corruption and lawlessness. Most inhabitants have seen few benefits from five decades of oil extraction that has damaged their environment.

The year-old administration of President Umaru YarAdua has repeatedly promised to address the root causes of the unrest.

But there is widespread skepticism over the government's handling of the problem and concerns about the future.

None of the many militant organizations in the Niger Delta has claimed responsibility for the latest abductions.