According to Militarymaps.info, the Ukrainian army has lost control over 95% of the Southern half of Donetsk oblast. Even some of the neighboring villages in the Zaporizhia oblast are under the threat of capture by the rebels.

http://militarymaps.info/

Only the port city of Mariupol and some of the adjoining towns and villages are currently under Kiev control.

Latest status map from Kot-Ivanov:

http://ic.pics.livejournal.com/kot_ivanov/71733898/25439/25439_original.jpg