Swedish Defense Minister Peter Hultqvist confirmed for Swedish Radio News that the foreign military plane was Russian and that it was flying with its transponder off.
"It's serious. It's inappropriate. It's downright dangerous," said Hultqvist. He also clarified for news agency TT that the incident took place in international air space, not in the Swedish skies.
The passenger plane had just lifted off from the Danish airport, Kastrup, when the military air traffic control noticed an "invisible" plane in the area.
Swedish and Danish fighter planes were sent up to identify it.
"The military plane had no transponder, but we discovered it via our radar system and warned the civil air traffic control in Malmö," Daniel Josefsson who works with combat management in Luleå, told the newspaper.
"All of a sudden, the military plane turned and I understood that in about a minute, it would be on a collision course with the passenger plane. We can see about how far it is between the planes, but can't determine the exact height. I contacted the civil air traffic control again, which then decided that the passenger plane would turn, and in that way, we avoided a catastrophe," Josefsson said.
According to Olle Sundin, director general of the Swedish Civil Aviation Administration, there are rules for how close planes can come to each other in the air, and in this case, the planes were clearly too close. He told DN that they still need to analyze their radar data to measure the distance, but that it is probably only the pilot of the passenger plane who can say how close they were.
"It could have ended really badly," Micael Bydén, chief of the Swedish Air Force told the newspaper.
In March this year, an SAS plane on the way from Kastrup to Rome was just 90 meters away from crashing into a Russian signals intelligence plane, which was also flying "invisibly", south of Malmö. Since then, military activity in the air space over the Baltic has increased, and according to the Swedish Civil Aviation Administration and to the Swedish Transport Agency, military planes are flying over the area daily without their transponders turned on, in order to avoid being discovered.