BRITISH OIL WORKER SEIZED FROM RIG

The attackers who boarded the Trident 8 rig left 23 other people on board unharmed, said Guy Cantwell, a spokesman for Houston-based Transocean Inc. He said the worker was a subcontractor on the rig that was working for Nigerian oil company ConOil.

The latest abduction brings to 22 the number of people seized in armed attacks within 36 hours in Nigeria's troubled southern oil region, where militants seeking greater control of the region's wealth and criminals kidnapping for ransom have stepped up attacks in recent days.

No demands were made by the gunmen who took away the British worker, Cantwell said.

Nigerian military spokesman Major Sagir Musa confirmed there was an "incident" on an offshore rig, but declined to give any details.

Nine of 21 hostages seized in three separate incidents on Thursday were freed the same day, while military negotiators have made contact with armed men still holding 11 foreigners also taken on the same day in an attack at a power plant.

Such kidnappings are rife in Africa's largest oil producer, where militants and criminals use them as leverage against the government, or to extract cash.

The latest kidnapping brings the total number of foreigners kidnapped in the Niger delta to at least 94 so far this year, more than the figure for all of last year. In 2006, more than 80 foreigners were seized in the region.

Nigeria is Africa's leading oil exporter and the United States' fifth-largest supplier, usually exporting 2.5 million barrels daily.

Unrest has plagued Nigeria's southern river delta region for years, and in recent months gunmen have stepped up a campaign against the oil industry, blowing up oil pipelines to cut production by a fifth and kidnapping scores of foreign workers. Most captives are released unharmed.