There can be no talk of a truce when a strategically important city is captured. Nothing could be further from the withdrawal of heavy weapons than attackers advancing in tanks under the massive use of rocket launchers. And the Minsk accord, designed as a roadmap to peace in eastern Ukraine, isn't even a week old yet.

In the battlefield town of Debaltseve, north of Donetsk, however, that peace process has possibly already been shot to smithereens in its early stages.

Even at the Minsk summit, there was not much hope for de-escalation in eastern Ukraine. In Debaltseve, the separatists completely ignored the first two goals of the 13-point accord: truce and the withdrawal of heavy weapons. They massively broke the ceasefire in order to create a precedent. Thus, they made sure all diplomatic efforts come to nothing.

Apparently, this happened with Russia's approval.

In a downright provocative manner, Russian President Vladimir Putin made as much clear Tuesday at a press conference in Hungary - an EU member state that borders Ukraine, too.

He declared the political leadership in Kyiv solely responsible for the bloodbath in Debaltseve; Putin even demanded the Ukrainian army should capitulate. He could not have shaped his words more clearly to express his partisanship for the separatists' conquest plans.

Humiliating defeat

The fall of Debaltseve is not just a military disaster for Ukraine's President Petro Poroshenko, but a political disaster. He faces massive domestic criticism of the Minsk accord, negotiated in tough talks between Ukraine, the pro-Russian separatists and heads of state and government from Germany, France and Russia. The document is fraught with compromises that are painful for Kyiv. Under Russia's influence, a "frozen conflict" and a separatist state structure have virtually been created on Ukrainian soil.

It was evident even in Minsk that neither the separatists nor Russia would accept a Ukrainian Debaltseve. The main road and train connection between Donetsk and Luhansk runs right through the town, linking the two "People's Republics" in terms of access. In addition, the railway line continues to Russia from Debaltseve, making it so much easier to ship military supplies to the separatists.

For weeks, the Ukrainian army was surrounded in Debaltseve. It didn't stand a chance in the face of an opponent armed with modern Russian weapons. But Poroshenko didn't want to give in, urging the troops instead to bear up. Now the defeated Ukrainian troops have to pull out of Debaltseve. The defeat is humiliating for Poroschenko, who is bound to come under increased domestic pressure.

Diplomacy alone is not enough

Most Ukrainians realize that, left alone in the military field, they can't win the war. That is why diplomatic efforts must continue. Should the pro-Russian fighters stop their advance after the fall of Debaltseve, there is still a chance to save the Minsk peace accord.

But danger looms on the horizon: From Debaltseve, it's not too far to Kharkiv, a major city in Ukraine's north. Mariupol in southern Ukraine is also still in the separatists' cross hairs. The war can still escalate even further.

Perhaps the separatists will be satisfied with the Luhansk and Donetsk regions. But the events in Debaltseve show that diplomacy alone, even on the highest level, won't stop land-robbing aggressors.

Should the pro-Russian fighters actually start moving on Kharkiv or Mariupol any time soon, the issue of weapons for Ukraine must be put on the agenda. In that case, additional sanctions against the separatists' Russian supporters would have to be arranged. European diplomacy has reached its limits.