This further escalation of the open armed conflict has tragic consequences for a population greatly suffering already for far too long. It would inevitably lead to a further grave deterioration of relations between the EU and Russia.

I call therefore openly upon Russia to use its considerable influence over separatist leaders and to stop any form of military, political or financial support. This would prevent disastrous consequences for all. Those responsible for the escalation must stop their hostile actions and live up to their commitments.

http://eeas.europa.eu/statements-eeas/2015/150124_01_en.htm