Eight foreign workers on an oil rig operating off Nigeria have been kidnapped, the rig's Norwegian owner said Friday.

The workers, six British, one American and one Canadian, were aboard the drilling rig Bulford Dolphin when it was attacked during the night, the Norway's Fred. Olsen Energy ASA said in a news release.

Countrywatch: Nigeria

It said Nigerian and other authorities were working to resolve the situation, adding Bulford Dolphin operated for the Nigerian oil company Peak Petroleum.

The statement said drilling from the rig had been temporarily suspended, but gave no other details.

The Bulford Dolphin is operated by Aberdeen, Scotland-based Dolphin Drilling Ltd., a subsidiary of Fred. Olsen Energy.

Nigerian militants have blown up oil pipelines and kidnapped foreign oil workers to press their demands for local control of oil revenues by inhabitants of the oil-producing south, who feel cheated out of the wealth produced in their backyards. Other groups have also kidnapped oil workers to use as bargaining chips to prod oil companies to increase jobs or improve benefits. The kidnappings usually end peacefully.

Last month, an unidentified gunman riding a motorcycle shot and killed an American riding in a car to work at the offices of the U.S. drilling equipment maker Baker Hughes Inc. in the southern Nigerian oil industry hub of Port Harcourt.