Updated

Kidnappers freed six foreigners Wednesday, including an American boat captain, abducted in a nightclub raid in Nigeria's southern oil region, the government said.

The six men were set free in the Port Harcourt area, the focus of a series of kidnapping in recent weeks, said Rivers state government spokesman Magnus Abe.

Militants opposed to Nigeria's oil policies are suspected in the abductions, but Abe said he couldn't confirm who carried them out.

The six were snatched 10 days ago by armed men who attacked the nightclub in the center Nigeria's oil hub of Port Harcourt, shooting into the air and sending scores of people rushing for cover. Officials said no one was injured in the incident.

Among those released was Royce Parfait, a commercial ship captain from Charleston, Tenn.

"I appreciate everything everybody's done for us. We're having champagne," Parfait told The Associated Press in brief comments over the phone following the release.

Also freed were two hostages from Britain and one each from Poland, Ireland and France. The men work for a range of oil and construction companies.

The rash of kidnappings in Port Harcourt — at least 17 in the past two weeks — prompted President Olusegun Obasanjo to declare a clampdown last week and at least 100 people were detained in police sweeps.

Ten other hostages were freed in recent days in addition to the six on Wednesday. A Lebanese man is still being held, Abe said. Hostages taken by militants looking for ransom are rarely harmed and most kidnappings end peacefully.

Hostage-takings in Nigeria — Africa's largest crude producer and a major U.S. supplier — have increased along with tensions between international oil firms and poor local communities.