It is not clear (and hardly ever is) who instigated the greater violence as the protests ramped up and the Ukrainian President called out the riot police.
The fact is that a group of potests formed over the President's actions with respect to several things, probably the final straw being the Ukraine-Russian deal announced by the Presidentand his unwillingness to back away from it. But there was more to it than that as the President ammassed more power to his office, and led a prgressively more oppulent and detahced life style.
As those protests grew, the local security force (not military) response to them also grew. From the many videos and pictures I have seen, and talks with Ukranians, that presence led to shoving, scuffles, fights, night sticks, etc.
At some point the molitav cocktails (fire bombs) and shooting started. Who knows who did what first?
The fact is, the shooting increased, as did protestor response to it...with more fire bombs, some handguns, shotguns, and rifles of their own.
I have several sources who tell me that requests for military crackdowns were considered by the administration...but flatly denied by the military. Whatever the whole story is, the protests coninued to heat up...the security forces attempts to stop them ramped up, scores of protestors were killed, security forces began to be overrun and captured, and some police units and others went whole sale over to the protestors. But the Ukrainian Military never intervened. They stayed in their barracks and bases. No heavy weapons were ever employed.
Ultimately, the protestors continued to make progress towards the government buildings. The Parliament became more animated..and ultimately it became clear to the President that the protestors were going to reach his government compound/housing/buildings/etc. and so either late Friday or early Saturday (Feb 21-22), he left.
Once he left the capitol..and his security forces vacated too...the Paliament met Saturday morning and at that point used the Ukranian constituional process to impeach him..and the porposal for impeachment carried, and he was officially and legally removed from office. There is now a warrant issued for his arrest.
That's where it is in Ukraine in the capital now. Crimea has had some unrest...but nothing compared to what went on in Kiev. The local government is still in control of the situation there, and apparently the former President is now in Russia. They are not sure.
Putin has postured in response to US blustering and held fairly large military exercises on the border. But there have been no incursions...and those exercises are now over. Through them, Putin made it clear he could have over 100,000 soldiers and hundreds of tanks and aircraft available at anytime within a few days time.
Hopefully it will settle down.
I expect that the Ukraine is going to have to allow even more autonomy for the Crimea. I hope, that even if there are protests or even violence there, that the Ukrainians will not make the same mistake Georgia made and walk headlong into a Vlademir Putin Russian Bear trap. If they don't act rashly, they may lose more influence over the Crimea...but they can also retain the vast majority of their country intact without any military confrontation and bloodletting.
I hope that peaceful otucome is what happens.