MOSCOW, May 5 (RAPSI / RIA Novosti) – Members of the Russian Civic Chamber are to file an application with the European Court of Human Rights (ECHR) against Ukraine over Odessa tragedy which left 46 dead, Izvestia daily reported Monday.

The Civic Chamber is gathering information at the moment, it is going to lodge an application afterwards, the newspaper quotes Georgy Fyodorov, a member of the Civic Chamber, as having said.

Mass protests led by pro-Russian activists are ongoing in eastern Ukraine's regions of Donetsk, Kharkiv and Lugansk. Ukraine saw Friday the bloodiest violence since the February overthrow of President Viktor Yanukovych, with dozens killed in clashes between local nationalists and pro-Russian activists across the country.

The highest casualty toll was reported in the southern Ukrainian city of Odessa where 46 people died and over 200 were injured in clashes between  nationalists from the Right Sector movement and their opponents. Over 170 people were detained in the aftermath of deadly riots, according to the Ukrainian Interior Ministry.

A two-day national mourning has been announced in the country.

In the meantime, members of the Russian Presidential Council for Civil Society and Human Rights request the UN, OSCE  and international human rights organizations to react on the tragedy in order to put an end to the bloodshed in Ukraine. The Council put the blame for the escalation of violence in the country on its federal authorities.