Four US hostages released in Nigeria - gov't

ABUJA, May 30 (Reuters) Four American hostages taken from Nigeria's oil-producing Niger Delta region were released today after three weeks in captivity, authorities said.

The four men were taken by gunmen from a barge working for US oil company Chevron off the coast of Nigeria on May 9, one of a series of kidnappings of foreign workers in the world's eighth largest oil exporter.

''The four American hostages have been released. The militants have handed them over to us,'' said Felix Ofore, a spokesman for the Delta state government.

The release leaves about 20 foreign hostages in the hands of various armed groups in the Niger Delta, a remote, impoverished wetlands region which is home to Africa's largest oil industry.

Militants fighting for regional control over the delta's oil wealth have sparked an upsurge in attacks on the oil industry since early 2006, reducing Nigerian oil exports by a quarter.

But the line between militancy and crime are blurred and most kidnappings are motivated by ransoms.

REUTERS CS SBA BST0207