Twenty Russian civilians were killed when two Ukrainian cities were shelled, Moscow has said.
According to the Russian defence ministry, the casualties were reported in the Ukrainian cities of Makiivka and Kramatorsk on Saturday night.
This news comes just a day after Russia launched a major aerial assault on the two towns with the apparent intent of seizing them back from Ukraine’s heavy pro-Russian forces.
The shelling of the cities has sparked fears of an escalation in the conflict between Ukraine and Russia, which has been brewing since 2014.
Russia’s Ministry of Defence said in a statement that the shelling was launched at the same time as the Moscow-led airstrike on the cities, a move which it said was intended to protect the population and help the local forces to secure victory.
The statement said that casualties were reported from both sides, but that the number of casualties among the Russian population was higher than on the Ukrainian side.
The Kiev government has denied launching the shelling, and has instead accused Moscow of using its assault to create a pretext for further military action in the region.
The shelling has caused outrage in Moscow and sparked calls for an investigation into the incident. President Vladimir Putin has demanded an explanation from the Ukrainian government and has threatened to take further action if the shelling is found to be the work of Ukrainian forces.
The conflict in Ukraine has been ongoing since 2014 when Russian forces annexed the Crimean peninsula. Over 2,000 people have since died as a result of the fighting.
The bombardment of these two cities, if proven to be true, could mark an acceleration in the conflict between Russia and Ukraine, a scenario that could have catastrophic consequences.