The mayor of the town on the Sea of Azov confirmed rebels had entered, as jubilant rebel supporters shared photos of advancing tanks on social media.
Ukrainian forces said they were still in “total control” of the town.
The rebels have been trying for weeks to break out of a near-encirclement further north in Donetsk.
Russia denies it is covertly supporting them on the ground.
I should be clear that I don’t think Russia is currently planning a full takeover of any part of eastern Ukraine. The goal remains what it has been for months now: to ensure that Ukraine remains unstable and weak. For now, in order to accomplish this goal, Russia needs to make sure the separatists are not defeated and remain a viable force. Both the escalation in assistance and the opening of the new front are a response to the losses that the separatists had suffered in recent weeks.
In the long run, the only acceptable end to the conflict for Russia is one that would either freeze the current situation in place with separatists in control of significant territory in eastern Ukraine (the Transnistria variant) or the removal of the pro-Western Ukrainian government and its replacement by a pro-Russian one. Participants in peace talks have to understand that this is essentially a red line for Moscow. Putin will not allow the restoration of control over eastern Ukraine by the current Ukrainian government by peaceful means and is clearly willing to directly involve Russian forces in military action to ensure that it doesn’t happen through a Ukrainian military victory.
As I argued some time ago, it was extremely unlikely that this conflict could end with a string of Ukrainian military victories. The pressure on Moscow to escalate, along with its likely dominance at higher levels of escalation, meant that Ukrainian gains were almost certainly going to spur a Russian reaction. At the same time, it was tough for the Kiev government to restrain itself, given its weak domestic position. Relenting while the Ukrainian military apparently held the upper hand would have opened a wide flank to the government’s nationalist critics.
At this point, however, Russia appears to be dealing the Ukrainian military a serious blow. Although this hurts, it also gives Kiev a way out; the Ukrainians cannot beat Russia, and no one thinks NATO intervention is plausible. The issue for Kiev now becomes to achieve a cease-fire before the Russians get to far. The question now is how strongly Russia and it proxies will play their hands. My bet is relative restraint (no march on Kiev), ensuring that the disputed provinces remain in Moscow’s orbit.
See also this excellent piece on Germany’s view of the crisis.