Russia's Black Sea Fleet on Mar 3 issued an ultimatum to Ukrainian forces in Crimea, giving the Ukrainian Navy until ‘1900’ local time, (12:00 Noon EST) to surrender or 'face a storm'. Ukrainian Army units in Crimea have until ‘0500’ local time Mar 4 (10:00 PM EST Mar 3) to surrender or endure an all-out assault.
Russia has not confirmed delivering any ultimatums; in fact they are not answering any phones or electronic methods of contact at all.
As the ultimatums went out, Russian Navy minesweepers and coastal ‘anti-submarine’ warships have arrived at the Russian naval base at Sevastopol. Ukraine’s Navy does have a few submarines, but their operational status is unclear in view of the defection of Ukraine’s top admiral.
The Russian warships that have arrived are coastal vessels which would likely be used for coastal reconnaissance and/or inserting special forces behind Ukrainian lines in addition to their designed naval missions. Russia already has larger warships in the Black Sea with which to do battle, some of which may be in port at Sevastopol.
On land in Crimea, Russian armor has now begun to arrive in Kerch in the form of main battle tanks. Kerch is just opposite Russia on the eastern side of the Crimean isthmus and is connected to Russia via vehicle ferry. During the Second World War, German forces used Kerch to evacuate troops cut off in the Caucuses region of Russia, after the German surrender at Stalingrad.
Russian troops in on the north side of Crimea are now digging in along the only land route into Crimea blocking any Ukrainian relief force that might attempt to break in. Ukraine does not have the capability to land troops by sea and then sustain such a force from the sea and the Russian Air Force now has tactical air superiority over the area, so any attempt at an air assault is out of the question.
Western and NATO leaders seem at the moment to be paralyzed in any response to Russian actions. British Foreign Secretary William Hague traveled to Kiev today and laid a wreath at Independence Square. U.S. Sec. of State John Kerry is expected to travel to Kiev soon.
However, outside of suggestions made by news media analysts commenting on the situation, nothing more has been proposed. Ukraine is not a member of NATO or even the European Union and has no defense pacts or treaties with any nation pertaining to defense of its territory.
Even if there were such arrangements, there is no appetite for military action in the United States and NATO forces have been in steady decay for a number of years in both size and readiness. Additionally, both NATO and U.S. forces have spent well over a decade in ‘gangland’ style combat rather than modern land and naval warfare against a professional military.