MOSCOW (AFP) - Russia on Monday said it was investigating the leader of a Ukrainian far-right group that clashed with riot police at Kiev protests for allegedly inciting acts of "terror" in Russia.

The powerful Investigative Committee said in a statement that it was seeking the arrest of the leader of the shadowy Right Sector paramilitary group, Dmytro Yarosh.

"In the opinion of investigators... Dmytro Yarosh publicly calls for anti-Russian forces to commit extremist acts and terror in Russia," the Investigative Committee said.

Investigators will shortly ask a court to arrest Yarosh in absentia and then put him on the international wanted list, it added.

If convicted of making calls to commit terrorist acts, Yarosh could face up to seven years in prison.

A teacher by training, Yarosh was born in the largely Russian-speaking eastern Ukraine. But he went on to create a Ukrainian nationalist group called Trident in 1994 inspired by Stepan Bandera, the guerrilla leader who fought Nazis, Soviets and Poles in World War II.

He founded Right Sector in November 2013 to coordinate radical forces at the Kiev protests. He was offered a post in the new Ukrainian Security Council but turned it down.

Hurling Molotov cocktails and cobble stones, the Right Sector activists made up the hard core of activists on Kiev's Independence Square who actively resisted riot police.

Yarosh has been repeatedly covered by Russian state television for allegedly writing on a social networking page on Saturday that he wanted Chechen rebel leader Doku Umarov to arm anti-Russian fighters.

The post prompted an angry response from a Russian foreign ministry official and from Chechen leader Ramzan Kadyrov.

Right Sector said the site had been hacked.

Russia's communications watchdog on Monday said it had blocked access to 13 Ukrainian nationalist communities on the country's most popular social networking site, VKontakte, over "direct calls to carry out terrorist activity and take part in unsanctioned mass rallies including in Moscow." Yarosh's page was among those blocked, Interfax news agency reported.

Russia on Sunday detained more than 300 activists at several protests against war in Ukraine in central Moscow, Ovdinfo, a group that monitors arrested activists, said.