SOLEDAR, Ukraine—Gen. Oleksandr Rozmaznin was taken aback when his Russian counterpart, assigned to help oversee the cease-fire in eastern Ukraine, announced on Jan. 20 that he would no longer show up at their joint office.
There was too great a security threat, Gen. Alexander Vyaznikov said, pointing to Grad rockets that had fallen nearby the day before, the latest in months of attacks.
“I said, ‘Well, I’m there. So if you know something I don’t know, maybe you can let me in on it,’” Gen. Rozmaznin said, recounting their exchanges. The Russian replied that he wanted to temporarily relocate because “there is a distinct threat to the life and health of my staff,” adding, “I invite you to follow my example.”
Soon enough, Russia-backed separatists launched a broad campaign to surround and seize the Ukrainian-held frontline city of Debaltseve, where the two were based. The Russian delegation’s pullout began to compute.
“They know the plans without a doubt,” Gen. Rozmaznin said.
Russia’s Defense Ministry didn’t respond to a request to interview Gen. Vyaznikov or to a list of emailed questions.
All sides had selected Debaltseve in September as the headquarters for a “joint center for coordination and control,” comprising Ukrainian and Russian officers and representatives from the two self-declared rebel republics. All were assigned to implement and monitor the cease-fire.
But the small city—a strategic railway hub for the region—has turned into the hottest battlefield in the conflict, the focal point of a surge in violence this past week that has rendered the nominal cease-fire more lifeless than ever.
Though the rebels have since trumpeted their offensive, Russian President Vladimir Putin has blamed the new fighting on Kiev, describing Ukrainian forces as “a foreign NATO legion, which is of course not pursuing Ukraine’s national interests.”
In the latest round of attacks, seven civilians were killed Friday by artillery fire in Debaltseve in their homes, regional police chief Vyacheslav Abroskin said on Facebook. Another seven civilians were killed in nearby rebel-held Donetsk, after shells landed near a bus stop and a humanitarian-aid distribution center.
Five members of the Ukrainian military were killed in the same 24-hour period, a spokesman said. Dozens were wounded on both sides.
Diplomats are scrambling to revive a new round of cease-fire talks over the weekend in the Belarusian capital of Minsk, hoping to bring a respite from the renewal of full-scale fighting.
Refusing to give up on the agreement, Gen. Rozmaznin says he hasn’t broken contact with his Russian counterpart and is trying to remain diplomatic. Meanwhile he says the rebels won’t succeed in their new offensive.
“With or without artillery, they won’t take Debaltseve,” the general said in an interview on Wednesday. “Because I’m telling you, we won’t let them do it. We won’t give it up.”
But the threat has grown by the day. On Friday, rebel leader Alexander Zakharchenko appeared on Russian state television amid burning buildings and artillery fire to claim his forces had taken the town of Vuhlehirsk, 6 miles down the road.
“Today, we tightened the ring around Debaltseve,” Mr. Zakharchenko said.
The transport hub, situated between the two largest rebel-held cities, Donetsk and Luhansk, is seen as vital to rebel efforts to restart their battered economy.
Ukrainian military spokesman Col. Andriy Lysenko denied that rebel forces had control of Vuhlehirsk and said a battle was underway. Authorities scrambled to evacuate thousands of remaining Debaltseve residents by bus.
Gen. Rozmaznin said that at first, implementation of at least part of the September cease-fire rules seemed plausible.
Ukrainian authorities provided accommodation and food for the Russian military’s working group representatives in Soledar, a Ukrainian salt-mining town, and work facilities in Debaltseve, about an hour’s drive away.
“It was written into the protocol that us two—the general from Russia and the general from Ukraine—would travel in the same car,” Gen. Rozmaznin said.
So for weeks, every workday morning they would sit together for the commute to Debaltseve along with a security detail, despite the veritable state of war between their countries.
The Organization for Security and Cooperation in Europe, which has the job of monitoring the activities of the implementation group, said the Russian representative voiced safety concerns after at least 30 Grad rockets hit Debaltseve on Jan. 19, killing three civilians and wounding 12.
The OSCE said the Russian delegation later handed an official letter to the Ukrainian team announcing its evacuation to Soledar. The OSCE conducted a crater analysis at the attack site and determined the missiles came from the direction of rebel-held territory to the west.
These days, Gen. Rozmaznin takes the car and goes to Debaltseve on his own. He says Gen. Vyaznikov stays behind in Soledar and gets around on foot. The security detail has split up so both generals remain guarded at all times.
“The Russians’ main task was to influence ‘those territories’ so they behaved themselves adequately,” Gen. Rozmaznin said. “But unfortunately…those comrades stopped behaving themselves adequately and started to intensify their efforts.”
He said the rebels regrouped, rearmed and decided to show Ukrainian forces their new strength.
At the core of the cease-fire working group are units of Russian and Ukrainian officers operating on both sides of the frontline, seeking to keep tabs on violations and open lines of communication.
Gen. Rozmaznin held up a chart of recent violations. He said there were 34 on Jan. 1. One day this week he said there were 126. The amount of destruction in the area would suggest even more. He said the bulk were from the rebel side, but the Ukrainians were also on the chart.
For the 60-year-old general, the fight in east Ukraine is personal. Though he spent much of his life moving around the Soviet Union with the Red Army, he grew up in the Luhansk region, a center of the separatist revolt. His wife comes from Donetsk, the neighboring region and the rebels’ other stronghold.
Gen. Rozmaznin led Ukrainian troops last summer in an attempt to secure the border there with Russia—a critical part of the cease-fire agreement that remains unfulfilled. He said coming under fire in a place where he used to run around as a boy was a “kind of moral trauma.”
“It wasn’t so much disappointment as pain and anger that weighed on me,” he said.
If the West were to supply arms to the Ukrainian military, he said, that could level the playing field, potentially creating an equilibrium that would force Russia to negotiate.
“If we had precision antitank weapons, for example, then it would mean their tanks would be destroyed in such quantities that it would probably bring them to their senses,” he said.
Western governments have consistently ruled out providing lethal military aid to Ukraine, which is not a member of the North Atlantic Treaty Organization, to avoid provoking a bigger confrontation with Russia. They have accused Russia of providing troops and materiel, charges Moscow has denied.
Like many top Ukrainian officials, Gen. Rosmaznin presents the conflict as a sort of civilizational battle.
“Europe should understand that Ukraine stands on frontier defending democracy and European values,” he said. “That is where we stand. That is what we’re defending. If we surrender, I have no doubt that the Baltics will be next.”