"Gangster-like" behavior in the modern world is unacceptable for any state, particularly for a permanent member of the UN Security Council, Ukrainian Premier Arseniy Yatseniuk has said.

"We [Ukrainians] consider that in this century, in this world, no country can behave similar to armed gangsters, particularly countries that are permanent members of the UN Security Council, and which were members of G8 previously. Russia must fulfill its international obligations. We demand one thing: fulfill international obligations and don't behave like gangsters in this century," Yatseniuk said during the joint press conference with U.S. Vice President Joseph Biden.

Besides, the premier again addressed to the Russian authorities "to immediately withdraw its special forces, which are deployed in the eastern Ukraine, and withdraw its army from Crimea."

"Once again I would like to state the position of the Ukrainian government: Ukraine will never recognize Crimea's annexation under any circumstances," Yatseniuk said.