The crisis in Ukraine continued to escalate on Thursday, as Russian President Vladimir Putin demanded Ukraine pull its military forces from some of its eastern regions.

Clashes intensified in the eastern city of Donetsk, where a pro-Russian separatist mob stormed the state prosecutor's office and forced the riot police sent to protect the building to surrender.

Donetsk is in one of two regions under heavy threat levels as the pro-Russian separatists continue to make advances in the eastern parts of the country, a little more than a month after Russia formally annexed the region of Crimea.

Sergii Gorbachov of Information Resistance posted a map on Wednesday featured on the site Voices of Ukraine (run here with permission) that sums up the current unrest:

Along with Donetsk, the Luhansk region is currently under threat of being controlled by the pro-Russian separatists. As the key shows, separatists have seized administrative buildings, there have been mass separatist rallies, and separatists have attacked pro-Ukrainian rallies in both of the regions. There is also the threat of raids by other, subversive groups and the ultimate threat of a Russian invasion.

Kharkiv is the region most threatened after the two hot zones. There have been mass separatist rallies in the region, as well as separatist attacks on pro-Ukrainian rallies. The region of Odesa, the southern-most region currently a part of Ukraine, is also under a moderate threat.

Crimea represents one-third of the region Putin has repeatedly referred to as "Novorussia," or "New Russia." The so-called "Green Men" in both Donetsk and Luhansk have called for referendums on sovereignty.

Putin called German Chancellor Angela Merkel the day before she was scheduled to meet with President Barack Obama during a visit to the United States. On Wednesday, Ukraine's acting president said he had lost control of some of his country's eastern regions.