A diplomatic offensive is being ratcheted up with both German and British leaders having telephoned Russian President Vladimir Putin urging him to pull back from Crimea.
Chancellor Angela Merkel is said to have warned him that sanctions would follow if a contact group seeking a political solution was not formed soon.
But German and British criticism that a planned Moscow-backed referendum on whether Crimea should join Russia was illegal were batted away by Putin.
On the ground, pro-Russian forces appear to have have tightened the psychological screws on the Ukrainian military.
There are reports that unidentified pro-Russia troops have seized an airport in the west of Crimea and taken over a border post detaining 30 Ukranian soldiers. No shots were fired.
Although Kyiv says it has no plans to send an army to the region, it has released a video of its military in training.
Russia continues to insist it has no troops in Crimea outside its Black Sea fleet naval base.