Ukrainian Prime Minister Arseniy Yatseniuk has said that the Russian leadership is responsible for the escalation of the conflict in the Autonomous Republic of Crimea.

"We are appealing to Russia. The Russian Federation must immediately cancel the referendum in the Autonomous Republic of Crimea (which is an integral part of Ukraine), and any talk that this referendum is being held by the Crimean authorities is false. There are no legitimate Crimean authorities: there is a group of criminals who seized power in Crimea in an unconstitutional manner under the guise of 18,000 Russian troops," he said at a press conference in Kyiv on Monday.

"It is the personal responsibility of Russia and the Russian leadership for everything that is happening in Crimea," he added.

Yatseniuk said that Ukraine had asked the international community to send observers to Crimea, but Russian military do not let them into the autonomy.