Police are searching for a Russian soldier suspected of shooting dead six of his comrades in eastern Ukraine, according to reports. The manhunt comes as a Russian officer went on trial for killing seven soldiers under his command after he threw a grenade into a room last year.

Since the start of Vladimir Putin’s full-scale invasion of Ukraine, there have been repeated claims of low morale among Russian troops, with the reasons ranging from unhappiness with training and equipment, to questioning the leadership of superiors.

Moscow’s war effort has been boosted by convicts who have been offered freedom if they serve for six months, although Russia’s forces are now said to be relying less on prisoners from the country’s penal colonies.