Prime Minister Jens Stoltenberg (R) and Minister Of Foreign Affairs Espen Barth Eide address a press conference on January 16, 2013 in Oslo, Norway on the hostage-taking at a Norway's energy group Statoil gas plant in Algeria. - 

A military operation is underway to free hostages, including several Americans, being held at a natural gas facility in Algeria. It's believed the action may be in response to French military operations against Islamist militants in neighbouring Mali.

The kidnappers, which Algeria says are linked to a senior al-Qaeda commander in the region, occupied the plant on Wednesday morning and took many workers captive.

The plant supplies gas to Europe and is a joint operation between BP, Norwegian energy firm Statoil, and Algeria's state oil company Sonatrach.

Reports suggest some of the hostages may have escaped while others have been killed during the operation by Algerian government forces.

The BBC's security correspondent Gordon Correra says these facilities are rarely targeted and the crisis will raise questions about the level of security that companies and governments provide for foreign energy workers at other potentially vulnerable sites.