Officials in the oil-industry centre of Port Harcourt confirmed a prison break, but had no further details.


Fighters seeking greater control of oil funds for their impoverished region have stepped up their attacks on Nigeria's oil industry in recent months, blowing up pipelines and kidnapping workers.


More than 80 workers were kidnapped last year and dozens more have been seized this month, with more than three dozen foreign workers currently in captivity. Hostages are rarely harmed by their captors, but there have been casualties in gunfights when Nigerian security forces confront the kidnappers.


Despite the region's great oil wealth, most of the region's people are mired in deep poverty that they blame on corrupt government officials and unfair contracts with the international oil companies that pump most of the crude.