The recent deployment of Russian troops along Ukraine’s border and Moscow’s indication that it could intervene in the event of a full-scale war in eastern Ukraine are dimming hopes for a peaceful resolution of the conflict that has festered for seven years and cost thousands of lives. Kremlin spokesman Dmitry Peskov told reporters on Friday that Russia had the right to move its forces across its territory at its discretion and was simply taking precautions given the “dangerous, explosive region at its borders” with eastern Ukraine.

Mr. Peskov warned that the situation on the contact line was extremely unstable and said “the dynamics…create the danger of a resumption of full-scale hostilities.” Russian President Vladimir Putin accused Ukraine of resuming “dangerous provocative actions” in its eastern Donbas region, in a call Friday with Turkish President Recep Tayyip Erdogan, according to a readout from the Kremlin.

Tensions have continued to mount between Ukraine and pro-Russian separatists following a recent escalation of fighting along the demarcation line inside Ukraine, where Kyiv said several of its soldiers were killed last week. Dmitry Kozak, deputy chief of staff of Russia’s Presidential Executive Office, warned on Thursday that Moscow would be forced to defend its citizens living in eastern Ukraine in the event of all-out war, and said this would be “the beginning of the end for Ukraine.”