Norwegian government officials say kidnappers have abducted four crew members from a Norwegian supply ship off the coast of Nigeria.
The officials identified the hostages as two Norwegian and two Ukrainian workers. One of the Norwegian captives is reported to be the ship's captain.
The Norwegian Foreign Ministry says the abductions occurred late Tuesday when the kidnappers boarded the ship "Northern Comrade."
A spokesman for the ship's operator says the kidnappers have not yet demanded a ransom. Police have not named any suspects.
Kidnappers still have not released four workers: a German and three Filipinos abducted last week in two separate incidents.
Abductions are common in Nigeria, especially in the oil-rich Delta region. Local militants want residents to receive more oil revenues.
Recent attacks on oil facilities and kidnappings have cut oil production by at least 20 percent since February. Nigeria normally produces 2.5 million barrels of oil per day.Some information for this report was provided by AFP, AP and Reuters.