LAGOS, Nigeria (AP) — Gunmen have freed three foreign workers, two  from the U.S., kidnapped from a ship supplying a Chevron Corp. offshore  oil field near Nigeria's coast, authorities said Friday.
The U.S.  Embassy in Abuja and Chevron separately confirmed the release of the  kidnapped workers from contractor Edison Chouest Offshore, based in  Galliano, Louisiana. A spokesman for Edison Chouest could not be  immediately reached for comment Friday.
Both organizations refused  to give further details about the workers' conditions or whether ransom  had been paid to secure their freedom after two weeks in captivity in  Nigeria's oil-rich, but violent southern delta.
Eight gunmen  attacked their ship as it idled Nov. 17 near Chevron's massive Agbami  oil field, operated by its Nigerian subsidiary about 70 nautical miles  offshore from Bayelsa state in Nigeria's Niger Delta, officials said.
Foreign  firms have pumped oil out of Nigeria's Niger Delta for more than 50  years. Despite the billions flowing into the nation's government, many  in the delta remain desperately poor, living in polluted waters without  access to proper medical care, education or work.
In 2006,  militants started a wave of attacks targeting foreign oil companies,  including bombing their pipelines, kidnapping their workers and fighting  with security forces. That violence waned in 2009 with a  government-sponsored amnesty program promising ex-fighters monthly  payments and job training. However, few in the delta have seen the  promised benefits.
No militant group operating in the delta  claimed responsibility for the kidnapping. It came after Exxon Mobil  Corp. has seen other contract workers kidnapped in recent weeks.  Analysts warn the attacks may signify a fraying of the amnesty deal.
Meanwhile,  attacks on crude oil tankers continue to rise around Nigeria, as  pirates take over vessels to steal the crude oil or gasoline held in  their holds.
The Agbami field is Nigeria's biggest offshore oil  producer, with a production capacity of as many as 250,000 barrels a  day, Chevron has said.
Nigeria, an OPEC member nation producing about 2.4 million barrels of crude oil a day, is a top supplier to the U.S.
  Jon Gambrell can be reached at www.twitter.com/jongambrellAP.
