NATO condemns Russia's military escalation in Crimea and expresses concern about the decision by the Federation Council of Russia's Federal Assembly to use Russian armed forces on the territory of Ukraine.

NATO said this in a statement after a meeting of the North Atlantic Council and the NATO-Ukraine Commission in Brussels on Sunday, Interfax-Ukraine reports.

"Military action against Ukraine by forces of the Russian Federation is a breach of international law. It contravenes the principles of the NATO-Russia Council and the Partnership for Peace. Russia must respect its obligations under the United Nations Charter and the spirit and principles of the Organization for Security and Cooperation in Europe, on which peace and stability in Europe rest. We call on Russia to de-escalate tensions," the statement reads.

NATO says Ukraine is a valued partner for NATO and a founding member of the Partnership for Peace.

NATO Allies will continue to support Ukrainian sovereignty, independence, territorial integrity, and the right of the Ukrainian people to determine their own future, without outside interference.

Speaking at a press conference after the meeting on Sunday, NATO Secretary General Anders Fogh Rasmussen said that NATO intends to engage with Russia in the NATO-Russia Council.