The issue of deploying a UN peacekeeping mission at the Russian-Ukrainian border in Donbas is off the table as it would be contradicting the Minsk agreements on the ceasefire in the eastern Ukrainian region.
The Package of Measures for the Implementation of the Minsk Agreements do not mention peacekeeping missions. http://www.osce.org/ru/cio/140221?download=true
Instead, they do state that full Ukrainian government control has be restored over the state border, throughout the conflict zone. In addition, all foreign armed groups, weapons and mercenaries have to be withdrawn from Ukrainian territory under the OSCE monitoring.
Further debunk: http://theins.ru/antifake/71968