Tensions remain high between Russia and Ukraine in advance of the March 15 referendum on Crimean independence. Rallies in both countries Monday turned violent.
Pro-Russia demonstrators in eastern Ukraine broke through police barricades and seized a government building.
"We are waiting for you here. Glory to Russia!" one Russia supporter said.
One woman said Ukrainians are afraid to leave their houses in Crimea. She called armed soldiers with no insignia on their uniforms "terrorists" and the Crimean authorities "gangsters."
Meanwhile, Sergey Aksyonov, prime minister of Crimea's regional government, is gaining notoriety.
Nicknamed "the Goblin," the businessman-turned politician was hand-picked by President Vladimir Putin to help Russia advance its interests in the Crimea.
Aksyonov's political opponents say he once led a criminal gang that was involved in extortion rackets. He had a message for the Ukrainian troops committed to re-taking Crimea:
"We are not enemies with those soldiers who pledged loyalty to the Ukrainian state," he said. "They will be allowed to leave for Ukraine if they wish."
Crimean secessionists say next week's referendum will settle the issue once and for all.
President Barack Obama insists the vote will violate international law.
Meanwhile, former Secretary of Defense Robert Gates is warning Putin wants more than Crimea, saying he has a long-term strategy to recreate a Russian sphere of influence throughout the region.
"Frankly, I don't think he will stop in Ukraine until there is a government in Ukraine, in Kiev, that is essentially pro-Russia," Gates said.
Obama is scheduled to meet with Ukrainian Prime Minister Arseny Yatseniuk at the White House Wednesday.
Both men are hoping to find a diplomatic solution to the Crimean crisis.