This was a German cover operation to conceal the shipment of matériel (especially heavy weapons) by sea for use by the forces involved in 'Weserübung Nord' (April 1940).
This task was achieved by presenting the shipments as being merely the pre-ordered delivery of heavy equipment to the USSR via the Arctic route and of coke to the port of Narvik in northern Norway.
In support of the Gruppe I force destined for Narvik were the cargo vessel Bärenfels (army equipment, guns and ammunition) diverted to Bergen and sunk by British carrierborne air attack on 14 April, the cargo vessel Rauenfels (army equipment, guns and ammunition) sunk by the British destroyers Havock and Hostile while entering the Ofotfjord on 10 April, and the cargo vessel Alster (motor transport and military stores) captured by the British destroyer Icarus near Bodø on 10 April.
In support of the Gruppe II force destined for Trondheim were the supply ship Sao Paulo sunk off Bergen on 9 April after striking a mine laid by the Norwegian minelayer Tyr,
the cargo ship Levante, and supply ship Main captured and sunk on 9 April by the Norwegian destroyer Draug)
In support of the Gruppe III force destined for Stavanger was the cargo vessel Roda captured and sunk on 9 April by the Norwegian destroyer Æger.