Russia on Friday 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."

Russia said it was launching its own investigation because "today there is not one country in the world that is able to accept the obvious, that the actions of the Ukrainian authorities are criminal."

It cited last Sunday's deaths of Italian journalist Andrea Rocchelli and his assistant, Russian rights activist Andrei Mironov, in a firefight in the rebel-held flashpoint of Slavyansk and the week-long detention of two Russian journalists from a pro-Kremlin website Life News by Ukrainian security forces.

It also listed the deaths of wounded rebels being transported in an open truck during a raid on Donetsk airport this week.

It mentioned the "bombardment of the cities of Slavyansk, Kramatorsk, Donetsk, Mariupol and other residential areas in the proclaimed Donestk and Lugansk People's Republics."

Russia believes Ukraine's armed forces "deliberately, with the aim of murdering peaceful citizens, used weapons, artillery, aviation, including with United Nations emblems and armament of combat vehicles and hardware."

"As a result, there are dead and wounded among the peaceful population," the Investigative Committee said.

It said that Ukrainian armed forces had also partly or wholly destroyed infrastructure including "hospitals, kindergartens and schools."

"The actions against the peaceful population have forced a number of residents of the Republic of Ukraine and the Donetsk and Lugansk people's republics, some of them Russian citizens, to flee their homes," it said.