Crimea Ukraine Russia Referendum Yanukovich Putin Obama
Head of the All-Ukrainian Union Svoboda (Freedom) Party Oleg Tyagnibok attends an anti-government rally in KievReuters

Russia has initiated a criminal case against the leader of Ukraine's opposition Svoboda party Oleh Tyagnibok for forming an armed group with intent to commit assault, according to Interfax news agency.

Investigative Committee spokesman Vladimir Markin told Interfax that Tyagnibok supported Chechen separatists in the 1990s and is now being prosecuted for organising an armed gang.

"Depending on the role of each of them, they are suspected of crimes punishable under Article 209 of the Criminal Code of the Russian Federation - 'formation of a stable armed group (gang) with the objective of assaults, leadership of such a group (gang), and participation in assaults committed by it," said Markin.

The criminal case is to include members of the Ukrainian National Assembly-Ukrainian People's Self-Defense (UNA-UNSO), accusing them of also organising an armed group.

Markin told Interfax that investigators of a Chechen battle between a Russian airborne division and Chechen separatist forces in 1994-95 had obtained evidence that the separatist militants included a unit of UNA-UNSO members.

The unit was led by brothers Oleh and Andriy Tyagnibok along with Dmytro Yarosh, Ukrainian leader of the far-right Pravy Sektor (Right Sector) paramilitary movement, Markin continued.

A Moscow court has issued an arrest warrant for Yarosh in abstentia.

The Investigative Committee spokesman said that its North Caucasus branch had gathered enough evidence to charge the accused opposition leader.