Military officials in southern Nigeria say a Romanian man seized from an oil tanker Wednesday has been released.
Army spokesman Lieutenant Colonel Sagir Musa confirmed the man's release but offered no details.
The worker was seized during an attack on the oil tanker M.T. near Nigeria's southern coast.
The main militant group in the area, the Movement for the Emancipation of the Niger Delta, issued a statement saying one of its affiliate groups carried out the attack. The group had said it would work for the man's safe release.
Kidnappings and violence are common in the Niger Delta, where militant groups are demanding the government share more of the region's oil wealth with local residents.
The attacks have cut Nigeria's oil production by about 20 percent from its peak in 2005.