Two Jas 39 Gripen deployed to avert a possible terror attack.

• How Norwegian police tricked terror suspects

A Norwegian Airlines plane en route from Spain to Sweden didn't respond when Swedish aviation authorities tried to contact the pilots. Also Danish and German air traffic control failed to reach the charter flight. It was German authorities who alerted their Swedish peers.

The faulty communication caused a military alert. Sweden deployed two fighter planes - Jas 39 Gripen - to avert the possible terror attack, according to tabloid Expressen.

The crew had mistakenly tuned into the wrong radio frequency, the airline said.

“It was a bit of an overreaction, if they had tried on a different frequency they probably had made contact”, Norwegian spokeswoman Anne-Sissel Skånvik told the newspaper. “There was never any danger associated with what happened”.

The incident took place July 13.