Russia yesterday accused Kiev's armed forces of breaching international law protecting civilians in wartime by killing and wounding peaceful citizens as it fights pro-Russian insurgents.
The Investigative Committee, the Russian equivalent of the FBI, said in a statement that Ukraine's armed forces as well as its National Guard and the Right Sector ultra-nationalist group caused civilian deaths "in breach of the Geneva Convention of 1949 on protecting the civilian population in time of war."
"Those guilty of the deaths of peaceful civilians and children according to all the canons of international law must bear responsibility for this," the statement said.
Russia said it had opened a criminal case under Russian law to probe "the use of banned means and methods in fighting a war."
A second team of European monitors was reported missing in restive eastern yesterday despite army claims it had regained control over much of the separatist rust belt. Earlier, a team of OSCE who went missing on Monday was confirmed detained by separatists on charge of spying.
The United States meanwhile voiced growing concern over the sudden appearance of fighters from Russia's war-ravaged Chechnya among rebels who have been waging a seven-week insurgency against Kiev's rule.
The increasingly volatile conflict -- growing ever more complex as rivalries emerge among rebel commanders -- has ensnared a steadily climbing number of Europeans tasked with helping to resolve a crisis that has threatened the very survival of Ukraine.
Western leaders have long accused the Kremlin of choreographing the insurgency in order to upset the rule of the European-aligned team that rose to power in Kiev in February -- a charge Russian President Vladimir Putin denies.
The defence ministry said on Friday that the eastern insurgency has thus far claimed the lives of 49 Ukrainian servicemen and 128 civilians and separatists.