Interim Ukrainian President Oleksander Turchinov puts the army on full combat alert after Russia approved sending troops into his country.

.(SOUNDBITE) (Ukrainian) ACTING PRESIDENT OLEKSANDER TURCHINOV SAYING:

"There are no grounds for this act of aggression."

The announcement has spurred diplomatic efforts to resolve Ukraine's crisis.

The UN Security Council held an emergency session on Saturday.

. (SOUNDBITE) (English) U.S. AMBASSADOR TO THE UNITED NATIONS, SAMANTHA POWER, SAYING:

"There is a clear way forward that would preserve Ukraine's sovereignty, territorial integrity and address Russia's concerns. First, Russia should directly engage the government of Ukraine. Second, international monitors and observers including from the U.N. and OSCE should be sent to Ukraine. That is the best way to get the facts, monitor conduct and to prevent any abuses. Russia is a leading member of both institutions and can participate actively to ensure that its int