Ukraine is struggling to keep control of key cities in its pro-Russian east as demonstrators seize government buildings and demand votes on joining Russia.
Authorities say shots were fired and at least 60 protesters arrested in Kharkiv Tuesday, while pro-Russian demonstrators held on to government offices captured Sunday in Donetsk.
In Luhansk, Ukrainian authorities say more than 50 people were allowed to leave state security headquarters early Wednesday, where the pro-Russians were allegedly holding 60 hostages. The officials say the protesters have wired the building with explosives.
U.S. Secretary of State John Kerry accused Russian agents and special forces of stoking separatist unrest in eastern Ukraine. He called the Russian actions "a contrived pretext for military intervention just as we saw in Crimea."
Kerry told a senate committee Tuesday that Moscow's involvement in Ukraine "clear and unmistakable." He said President Barack Obama is preparing more tough sanctions on Russia if it continues destabilizing Ukraine.