Ukraine is a country divided. This has been brewing ever since the break-up of the Soviet Union and Ukrainian independence.
You may be wondering, then, why there is such a consistent and deep divide between these two halves of Ukraine. Here's the really crucial thing to understand about Ukraine: A whole lot of the country speaks Russian, rather than Ukrainian. This map shows the country's linguistic divide, which you may notice lines up just about perfectly with its political divide.
http://www.washingtonpost.com
Protests in Ukraine are not pro-EU (as it is written in most of international news agencies). The disruption of the association agreement with the European Union in November was only cause for local rallies. But after a peaceful student protest was violently dispersed by the 'Berkut' [special police] in Kyiv on Nov. 30, angry people took to the central square of the capital.