Updated at 2 p.m. ET
LAGOS, Nigeria - A U.S. citizen kidnapped by gunmen in Nigeria's oil-rich southern delta has been freed after a week in captivity, the U.S. Embassy said Friday.
U.S. Embassy spokeswoman Deb MacLean told The Associated Press that the man had been released after being kidnapped in Warri in Delta state on Jan. 20. MacLean declined to offer any other details, citing privacy rules. Delta state police spokesman Charles Muka said he had not been informed about the man's release, as his company refused to cooperate with local authorities.
The freed hostage was identified as William Gregory Ock, 50, of Bowdon, Ga., by his sister, Dee Dee Patterson.
Patterson told the AP on Friday that the family had no details of his release.
"The only thing we know is that he is safe and he is in a secure location," Patterson said by telephone.
She had no information on when Ock would return home to Georgia.
It was not immediately clear whether a ransom had been paid to secure his release, though many companies working in the region carry kidnap insurance and simply pay a negotiated price to see their employees freed. Kidnappers had made contact with authorities previously and demanded a $333,000 ransom.
The attack Jan. 20 occurred outside a bank branch in Warri, one of the main cities in nation's Niger Delta, a region of mangroves and swamps where foreign oil companies pump 2.4 million barrels of crude oil a day. The gunmen attacked Ock as he came outside, shooting his police escort to death before abducting him, Muka said.
Investigators believe the gunmen trailed him for some time before the attack, Muka said.
Foreign firms have pumped oil out of the delta for more than 50 years. Despite the billions flowing into Nigeria'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 and criminal gangs still roam the region, increasingly targeting middle-class Nigerians.
In 2011, there were five reported kidnappings of U.S. citizens in Nigeria, according to a recent U.S. State Department travel warning about the country. The most recent occurred in November when two U.S. citizens and a Mexican were kidnapped from a Chevron Corp. offshore oil field and held for about two weeks, the State Department said.
A German working in the city of Kano in north Nigeria was abducted Thursday by unknown gunmen, authorities have said.