Ukraine has been in crisis for the past few weeks following the refusal of their President to sign an Association Agreement with the European Union which had already been agreed. He had been blackmailed by Soviet (and I mean that) President Putin who threatened in effect to cut off the country's gas supply if it does not continue to cowtow to the Kremlin.
The division is one between those who wish to go back to the old Comintern trading agreement or face west to join the European Union in the long term - Association agreements are the first stage in harmonizing the economic system with that of the EU - including such things as dealing with corruption - in advance of a formal entry negotiation.
Those in favor of the EU agreement have been occupying Independence Square in the capital Kiev. Some have put the numbers in the main Sunday demonstrations as higher than in the "Rose revolution" which overthrew the old Communist government.
Tonight temperatures are below freezing and around 4 am local time huge contingents of police have moved in in and attempt to clear the square. Non-violent actions by the protesters have included spreading water on the ground so it turns to ice and makes the police advance difficult on the resulting ice. Despite this it looks like the clearing is going to get violent. Tear gas has already been fired and scuffles are reported.