HORLIVKA, Ukraine — The rebel commander casually led the way down a muddy trench, shoulder high with shaved walls of moist earth, his boots slapping at wooden slabs sunk into the muck. Finally, he reached an earth-covered observation post.
“There, you see,” he said, pointing a gnarled index finger, its brown nail twisted after 30 years in the coal mines. A few hundred yards away, across an icy lake and a field, were some scattered office buildings, close enough to count the windowpanes.
“There are the Ukrainians,” said the commander, whose real name is Pavel and who asked that his surname not be used, for fear of reprisals. His fighters call him Batya, an endearment for father in Russian and a common nom de guerre for rebel commanders in eastern Ukraine.
The smack of artillery fire rose from a village in the valley below, captured just a few days earlier by Batya’s rebels. A nearby crack, a tense pause, then a distant thud somewhere beyond the lake.
“Sometimes, at night, they come at us with their tanks,” Batya said. “But we do not let them advance.”
The mood here on the rebel front lines is upbeat these days. Two weeks ago, Russian-backed rebels captured the airport in Donetsk, kicking off the fiercest round of combat in the region since last fall. Their commanders declared a four-month-old cease-fire defunct and vowed new attacks, which began almost immediately, including one in which a barrage of rockets struck a crowded market in a Black Sea coastal town, Mariupol, that left 31 dead.
The conflict in eastern Ukraine exploded nearly a year ago, after the government of President Viktor F. Yanukovych was toppled by pro-Western forces. Since then, more than 5,000 people have died as the separatists, backed by Russian money, strategic guidance, weapons and, NATO says, troops, have defeated all of Kiev’s efforts to bring them back into the fold.
Now, powered by what Western officials say was a fresh injection of Russian aid last month, the rebels feel they have the upper hand.
On Monday, the top commander, Aleksandr Zakharchenko, said that the rebels would answer Ukraine’s recent announcement that it would conscript more troops by organizing a voluntary mobilization of their own that, he vowed, would increase the size of the rebel army to as many as 100,000.
At the moment, the rebels are within reach of surrounding a contingent of hundreds of Ukrainian troops dug into the town of Debaltseve, a crucial rail hub. “We are on the move and they are trapped,” Batya said.
His fighters are deployed on the edge of the strategic city of Horlivka, not far from the only road still connecting Debaltseve — 23 miles to the east — with Ukrainian-controlled territory to the north. The road has come under regular fire in recent days and is sometimes impassable.
The grand house where Batya and his troops make their headquarters used to belong to a regional prosecutor. But he fled in the face of the separatist advance, so now the rebels are lords of the manor. The soaring, two-story entryway, wrapped in a grand wooden staircase, is now the company canteen, a pot of bubbling stew perfuming the air, boxes of medical supplies stacked in the corner.
Batya makes his office in a front parlor, chattering on walkie-talkies with his troops while his top fighters smoke cigarettes on a sofa and flick ashes into a shell casing.
“This is our famous fighter,” he said, laughing happily and gesturing to a small woman seated beside the window. Her name is Ira, and before the war she was the secretary at a kindergarten in Shakhtarsk, a town several miles to the south. Batya is from the same town, as are most of his fighters — outside of a couple who described themselves as volunteers from Russia.
“She is known as 01,” he said, pronouncing it “zero one,” which is an emergency telephone number, like 911 in America. “She goes into the field to rescue our fighters when they are wounded. Plus she is our best sniper. She can cook for us. She can drive our tank.”
He reached into a corner behind a tattered chair and pulled out a long rifle with a thick scope. “Here is her sniper rifle,” he said.
Ira sat on the sofa, blushing slightly and rubbing her feet together, clad in fuzzy red slippers.
She had no sniper training. “I just decided to give it a try,” she said.
Batya barked a few orders into his walkie-talkie, then turned and said, “There will be loud noises soon.” Almost instantly, the company’s tank, parked down the road, barked loudly and the percussion wave rolled up the venetian blinds.
Batya said his troops had held this position for four months, but were looking forward to moving once the road to Debaltseve is severed. After that, well, that is another question.
In August, Russian-backed rebel troops routed Ukrainian forces around the town of Ilovaisk, obliterating entire units of soldiers, leaving about 100 armored vehicles in smoking ruins and reversing the tide of the war. There is talk now of “another Ilovaisk” in Debaltseve.
“We will win, I know that,” Batya said. “We will not accept to live with these Ukrainians any more. But what the world will look like after the fighting, really, I don’t know.”
The venetian blinds danced a few more times. Coffee was served and Ira traded her fuzzy slippers for leather boots and a fur-lined combat cap. Batya fingered the medals hanging from his battle tunic; one of them is for conspicuous bravery, the highest decoration the rebels bestow.
Horlivka is a crucial position for the rebels, both because of its substantial industrial facilities and because of five huge water pipelines that converge here. If Ukraine captures the town, Batya said, it could choke off the entire region’s water supply.
“Lose Horlivka and we lose the war,” he said. “But we do not lose Horlivka.”
The streets in the center of town were crowded with shoppers over the weekend, most of them elderly women with pushcarts.
The billboards had not been changed for nearly a year, so the paper on them hung in shreds, layer upon layer, with only the occasional smiling eyeball or number peeking through. People waited at stoplights, ran for buses. A statue of Lenin peered sternly over a central square.
To the north, though, where the front lines meet the edge of town, street traffic was sparse. A bus stop had been blasted to bits. A pedestrian bridge collapsed onto a water pipe. A scorched ninth-floor apartment was all that was left of a family of three, hit with a shell two nights earlier.
At only one point did Batya’s mood sour, when he asked how Americans could support Ukrainian troops who were doing such things to his people.
“Do we look like terrorists?” he asked. “Do we look like Russian soldiers?”
He reached into his shoulder bag and pulled out a Ukrainian passport — “See!” he shouted — and then a stack of laminated ID cards, one for each of the towns in which he has fought, beginning with Slovyansk last spring.
“Every time we move to a new town, there are new forms to fill out,” Batya said, suddenly smiling again.
After a brief tour of the front lines, he paused at one of his northernmost emplacements, just to check the temperature of his troops. An elderly woman was arguing angrily with a pair of soldiers who refused to let her through to buy bread, fearing she was a Ukrainian spy.