Ukrainian Prime Minister Yatseniuk has said that "the Crimean issue" has moved from a political to a military stage as a result of Russia's actions.

"Now it actually switches from a political to a military stage due to the Russian military," he said in a joint statement with Chairman of the Verkhovna Rada of Ukraine, acting President Oleksandr Turchynov on Tuesday.

He noted that the responsibility for the military escalation of the conflict lies solely with the political leadership of Russia.

"Today, Russian military started shooting at Ukrainian servicemen, and this is a war crime that has no period of limitation," Yatseniuk said.