Second Russian airstrike kills 19 civilians in Deir az-Zor
UK-based Syrian Observatory for Human Rights said two sets of air strikes - half an hour apart - targeted the village of al-Khrayta, killed eight civilians living in tents along the Euphrates River.
Eleven civilians were also killed in boats crossing the water.
The deaths came a day after the monitor said Russian air strikes killed 34 civilians in ferries carrying them across the Euphrates, south-west of the city.
The Syrian Observatory for Human Rights monitor initially reported 21 deaths in Russian air strikes but later raised the toll to 34, after "more bodies have been found in the river".
The oppostion Syrian Coalition condemned the air strikes on Monday, describing them as "an endless litany of war crimes by the Russian invaders against the Syrian people amid complete international silence".
The Syrian conflict began when the Baath regime, in power since 1963 and led by Bashar al-Assad, responded with military force to peaceful protests demanding democratic reforms during the Arab Spring wave of uprisings.
It triggered an armed rebellion fuelled by mass defections from the Syrian army.
According to independent monitors, hundreds of thousands of civilians have been killed in the war, mostly by the regime and its powerful allies, and millions have been displaced both inside and outside of Syria.
As well as the use of chemical weapons, brutal tactics pursued mainly by the regime have included sieges, mass executions and torture against civilians, leading to war crimes investigations.