Two Explosions have been heard in Simferopol Crimea's capital

[The Straight Story]

A loud bang was heard about 23:10 local time (21:10 GMT), following by a smaller blast, BBC reporters in Simferopol say.

A city resident blogged about hearing an explosion come from the direction of Elevatornaya Street, where an electronic combat military unit is based.

Ukraine has ordered a full military mobilisation in response to Russia's build-up of its forces on the Crimean peninsula. Prime Minister Arseniy Yatsenyuk has warned the country is "on the brink of disaster".

In Crimea, Ukrainian soldiers faced off with Russian soldiers surrounding their bases on Sunday while the Russian army was said to be digging trenches on the border with mainland Ukraine.

http://www.bbc.com/news/world-europe-26410431

[left on green only]

1. At Least If They Are Digging Trenches On The Border........

It wouldn't seem like they are planning to invade, unless they are just polishing their shoveling techniques while they await the "time to invade" word.

[Igel]

2. They have to do something.

On the other hand, that's a really bad place to invade from. Narrow little chokepoint. Better to invade along the long border of the Donbas, blitzkrieg style so that the Ukrainian's wouldn't dare try to let the tanks through but would have a hard time figuring out where they'd come fromt.

That's if they want to get the partly ethnic-Russian territories on the east, claiming that since >50% are Russian-speaking that's prime territory. It would leave Crimea + East Ukraine non-contiguous, but perhaps the Krym's slated for direct annexation (reversion, I guess they'd call it) while the other will be a vassal state.

Most of the rest of Ukraine is 30-40% Russophone, and while Putin no doubt would like to see one Russophone per province as sufficient justification for annexation, I doubt he'd go that far. It would be a handy population for stirring up trouble. (Of course, most of that population is ethnically Ukrainian but Russified over the last 150 years.)