A Russian MiG-31 Foxhound interceptor/fighter crashed on Friday in the Perm region of the Urals, but the pilots ejected safely.
The Defense Ministry has grounded all MiG-31s following the crash.
A preliminary cause of the crash was that the plane went into a tailspin, a spokesman for the Investigative Committee's military department said.
The crash site has been located and investigators have arrived at the scene, he added.
Officials said the plane was not carrying any weapons and posed no danger to residential areas.
Defense Ministry spokesman Vladimir Drik said the pilots were "in a satisfactory condition."
MOSCOW/PERM, November 19 (RIA Novosti)