Two Russian servicemen have been killed in Deir al-Zor province after ISIS militants shelled a convoy they were escorting, the Russian Defence Ministry was cited as saying on Monday by the Interfax news agency.
The convoy was transporting Russian ceasefire monitoring military staff when it came under mortar attack, the ministry was quoted as saying.
One soldier was killed on the spot and the other died in hospital after sustaining serious injuries. Both were awarded posthumous military awards, the ministry said.
Russia said earlier on Monday that its air force was helping the Syrian army push ahead with an offensive on the Euphrates city of Deir al-Zor, where Islamic State has besieged 93,000 civilians and an army garrison for years.