The incident occurred over international waters on 3 March, as SAS flight SK 681 was on its way to Rome, according to the broadcaster. The Swedish flight changed course at the last moment to avoid the crash.
The Russian aircraft did not appear on the SAS plane's warning system, but was visually spotted by SAS pilots. The aircraft passed within 90 meters of each other, considerably less than the safety minimum of 300 meters, SVT reported.
The Russian aircraft was an Ilyushin Il-20M signals intelligence plane, Jens Olsson, a Swedish investigators at the Accident Investigation Board, told SVT.
The incident remained under investigation.