moscow russia military say thursday accomplish mission defeat islamic state syria remain settlements group control russian bombers use unprecedented force final stag finish militant group senior russian officer say mission defeat bandit units islamic state terrorist organization territory syria carry arm force russian federation accomplish colonel-general sergei rudskoi head general staff operations say rossiya 24 tv channel syrian government force comb de-mining areas islamic state strongholds say final stage defeat terrorists accompany unprecedented deployment intense combat use russia air force say air strike include 14 sorties group long-range bombers russia make past month say russia military deploy syria would focus preserve ceasefires restore peaceful life say russian military mission accomplish islamic state defeat syria