Three Filipino oil workers taken hostage in southern Nigeria were released in the presence of reporters early Monday after being held by unidentified captors for more than a week.

The men, kidnapped last Friday, were handed over to the Filipino ambassador in Nigeria's oil hub of Port Harcourt. They work for U.S. oil contractor Michael Baker Corp. of Moon Township, Pa.

A spokesman for the state governor did not provide information on who had taken the men or if a ransom was paid.

"The important thing is that the hostages have been released and not who captured them," Blesyn Wiki said.

CountryWatch: Nigeria

The three Filipinos looked worn out and were wearing the same clothes as when they were taken hostage. The men were driven off in a Jeep with the ambassador.

A colleague of the workers had said that armed men blocked their vehicle on Aug. 4 then forced them out at gunpoint.

No group has publicly claimed responsibility for either attack. The Movement for the Emancipation of the Niger Delta, which has kidnapped several foreigners in the past, said it was not involved.

Michael Baker said the men work for its Baker Energy unit, which builds structures for energy companies.

Kidnappings and pipeline attacks have become common in Nigeria's southern delta — an oil-rich region where local communities have sparred with multinational corporations in an effort to snatch a bit of the wealth pouring out of their land.

The attacks have cut oil production by more than a quarter this year, adding to the upward pressure on world prices. Nigeria is Africa's largest oil producer and a major supplier to the United States.

Hostages have usually been released unharmed by groups demanding either money or government concessions. Two Filipino oil workers kidnapped in June were released after five days in captivity.