US aircraft crashes in Norway, 4 dead

Rescue services reached the crash site early on Saturday after helicopters were unable to land due to poor weather conditions.

"Police reached the crash site at around 0130 CET (11.30 AEDT)," Ivar Bo Nilsson, head of the operation for Nordland police, said in a statement. 

"It is regrettably confirmed that all four on board the plane have perished." 

The four were all believed to be US nationals, police said.

An investigation of the cause of the crash has been stalled by poor weather, with work set to resume once conditions improve.

Some 30,000 troops from 27 countries are involved in Cold Response, an exercise designed to prepare NATO member countries for the defence of Norway.