The assault on facilities on the In Amenas field came as France steps up a military campaign against insurgents in neighbouring Mali.
In Amenas is jointly operated by UK supermajor BP, Statoil of Norway and Algerian state oil company Sonatrach.
British, American, Norwegian, Japanese, French and Irish personnel were reportedly kidnapped by assailants who launched the raid in up to 10 vehicles on the wet gas development field on Wednesday morning.
Heavily-armed
