Live Blog: Ukraine In Crisis (Archive)

"The responses of post-Soviet states (excluding the Baltics, which have also condemned Russia's actions) have been more mixed, reflecting the complex diplomatic environment and, in many cases, the imperative of retaining positive relations with Russia. Nevertheless, Russia appears to have received greater support in this crisis than after the war with Georgia in 2008, when no post-Soviet state joined it in recognising the independence of the breakaway territories of South Ossetia and Abkhazia. Privately, however, Russia's actions are likely to have caused alarm across the region."

At least two individuals are facing charges after activists supporting Russia clashed with rival demonstrators in Georgia on Thursday.

Twenty-five activists of the Earth Is Our Home nongovernmental organization held a rally on Pushkin Square in central Tbilisi on Thursday to express support for Russian officials targeted by sanctions imposed by the United States after Russia annexed Ukraine's Crimea.

Some of the activists at the rally were carrying Russian flags. Dozens of opponents arrived at the site and provoked the clashes.

According to various sources, police detained two or three individuals, who were charged with hooliganism and resisting police.

They were released later on Thursday but asked not to leave Tbilisi as their hearings were scheduled for Friday.

Muzychko played a key role in recent antigovernment demonstrations that led to the ouster of former President Viktor Yanukovych.

He was killed on the night of March 24-25 in the city of Rivne under unclear circumstances as police commandos attemped to detain him.

Muzychko was sought for organized-crime links, hooliganism, and threats to public officials.

On Thursday, hundreds of Right Sector supporters rallied outside the parliament building in Kyiv to demand that lawmakers investigate Muzychko's killing and consider the resignation of acting Interior Minister Arsen Avakov.

The Russian news agency ITAR-TASS said Friday it had received a written statement from Yanukovych calling for the referendum.

Yanukovych fled Ukraine in February and has been in Russia since then. Moscow considers him the legitimate head of the country.

Yanukovych said the Ukrainian government's plan to hold a presidential election in May could destabilize the country and only a national referendum can preserve Ukraine's sovereignty and territorial integrity. Yanukovych called the current authorities in Ukraine unconstitutional and said the situation amounts to "anarchy."

He also asked the Party of Regions to remove him as honorary chairman and to cancel his membership in the party.