The helicopters were taking part in military exercises when the accident occurred.
“There were four people on board, two in each helicopter,” said air force spokeswoman Nina Karlsson.
The aircraft belonged to the Linköping helicopter fleet but had taken off from the F17 airfield in Kallinge on Tuesday. Both craft were German-made Bölkow Bo 105s, known in Sweden as Helikopter 9s.
“They were supposed to pick up three people for battle control helicopter exercises,” said Nina Karlsson.
It is not yet known what might have caused the crash.
“We are going to travel down this evening but we probably won’t be able to do much until tomorrow,” said Agne Widholm, chief investigator for the Swedish Accident Investigation Board.
“If it was a mid-air collision I suspect that we will have to search for parts over quite a large area,” he added.
Freelance photographer Hans Runesson viewed the crash site from a nearby hunting tower.
“It’s all a wreck. There is hardly a trace of anything left, just one propeller sticking up,” he said.
Eye witness Charlotte Björnsson lives beside the site where the helicopters came to earth.
“The whole house shook, so I took the telephone and ran out to raise the alarm.
“It was then that I saw helicopter parts and half a helicopter falling down. Then smoke started coming from the nearby woods,” she told Smålandsposten.