MOSCOW, May 7 (RAPSI) – Russian investigators have extended the probe into Ukrainian ultra-nationalist Dmitry Yarosh, official spokesman for the Investigative Committee Vladimir Markin announced Wednesday.

Yarosh is considered to have been one of the leaders of the Ukrainian protest movement that recently uprooted Ukraine's power structure.

He stands accused in Russia of publicly endorsing extremism and terrorism in connection with an appeal he is suspected of having made to North Caucasus militant commander Doku Umarov. Specifically, Yarosh stands accused of asking for help with carrying out terror attacks on Russian soil.

Umarov, the self-proclaimed head of a secessionist group in the North Caucasus, has claimed responsibility for several terrorist attacks in Russia. He recently made international headlines after threatening to attack the Winter Olympics in Sochi.

Moscow's Basmanny District Court ordered Yarosh's arrest in absentia on March 11. Soon afterwards he appealed the order. On April 2, the Moscow City Court upheld an in-absentia arrest order issued against Yarosh.

The parliament of Crimea, which recently voted for its independence from Ukraine and its reunification with Russia, banned nationalist party Svoboda (Liberty) and ultra-nationalist political movement Right Sector, which is headed by Yarosh.