BEIRUT (Reuters) - The Syrian Observatory for Human Rights said air strikes likely to have been carried out by Russian warplanes have killed 69 people since Sunday (Sept 10) near the Euphrates River in the eastern Syrian province of Deir Ezzor.

The Russian Defence Ministry did not immediately respond to a Reuters request for comment on Tuesday's report by the Britain-based monitoring group.

The Observatory, which identified the victims as civilians, said the air strikes hit civilian encampments on the western bank of the Euphrates and vessels crossing the river to the eastern side.

Separately, Syrian state television said on Tuesday Islamic State in Iraq and Syria (ISIS) militants have been using the river to flee the city of Deir Ezzor.

With heavy artillery and machine guns, the Syrian army struck rafts carrying militants and crossing the Euphrates to the eastern side, it reported.

ISIS' "only escape route out of the city is through rafts on the river, and, God willing, we will target them in the water before they get away", a field commander in Deir Ezzor told state TV.