The Russian Air Force lost one of its Tupolev Tu-22M supersonic heavy bombers on Friday. The Ministry of Defence in Moscow announced the crash was presumably due to technical causes but Ukraine said the plane had been shot down. According to Moscow, the aircraft crashed in the Stavropol region of southern Russia while returning from a combat mission. The four crew members had ejected and three have so far been rescued. The aircraft had no ammunition on board, the ministry added. The reported crash site is around 600 kilometres behind the front line in Ukraine. Russian and Ukrainian military bl…