DRUZHKIVKA, UKRAINE (NYTIMES) - Ukrainian forces dug in for a last-ditch defence against Russian advances on Wednesday (June 22) in Luhansk province, where the invaders now threaten to overrun two major cities that had resisted their halting progress.
The prospect of a Russian takeover of the embattled cities, Sievierodonetsk and Lysychansk, left Ukrainian commanders with the stark choice to stay and fight, risking severed supply lines and the encirclement of thousands of defenders, or withdraw and forfeit the last major urban centres in Luhansk, part of eastern Ukraine's Donbas region.
For weeks, the Russians had been content to lay back and fire artillery and rockets on Ukrainian forces before trying to push forward with tanks and troops. This strategy culminated in an apparent breakthrough on Wednesday as the Russians seized three strategic villages, the regional governor of Luhansk, Serhiy Haidai, conceded.
From the villages - Mirna Dolina, Podlisne and Toshkivka - Russian troops have gained higher ground to fire on Lysychansk, including with shorter-range artillery.
"The last city is Lysychansk, and it will be very hard here, a lot of good guys will die," said Sergiy, a Ukrainian soldier defending the city who gave only his first name for security reasons.
While the villages are small, their collapse within days of one another amounts to a significant breach in Ukraine's defences, bringing Russian forces to the doorstep of Lysychansk and threatening the dwindling supply routes into the city.
"The surprising aspect here is that Ukraine has chosen to reinforce as Russian forces inch closer to the city," said Mr Michael Kofman, director of Russia studies at CNA, a research group in Virginia. "Both cities, Sievierodonetsk and Lysychansk, could fall in the near term."
That could open the way for Russia to seize Luhansk and neighbouring Donetsk province, known collectively as Donbas.
Still, military analysts suggested it was premature to say Russia was on the cusp of a decisive turn in its four-month-old invasion.
"Russia may not have the forces to exploit this localised offensive, and will find itself in a grinding fight against yet another set of Ukrainian defensive lines," Mr Kofman said.
The Russian advance was "a clear setback for Ukrainian defences" in the region, although not necessarily the sign of a broader collapse, according to the Institute for the Study of War, a research group based in Washington.
Taking Lysychansk will likely require "further protracted battles with Ukrainian forces" in close combat, the institute said, similar to the vicious, block-by-block street fighting in cities like Sievierodonetsk and the southern port city of Mariupol.
These protracted urban fights play into Ukraine's current strategy of bleeding Russian forces no matter the cost. Twisting alleyways and cramped neighbourhoods give Ukrainian troops proximity to their Russian foes, negating the advantage the invaders enjoy in long-range firepower.
Russia's recent gains have come at a high price, particularly to ill-equipped soldiers drawn from the Russian-backed separatist enclaves of Luhansk and Donetsk. British military intelligence officials said in a report on Wednesday that the pro-Moscow Donetsk militia had lost 55 per cent of its forces, killed or wounded, in the recent fighting.
Like Ukrainian forces who rely on a medley of different units to wage war, the Russians have committed Chechen forces and Wagner paramilitary units alongside the separatists and other uniformed troops.
Ukrainian forces, too, have suffered significant losses, and increasingly have been forced to re-staff their casualty-stricken ranks with poorly trained territorial defence units to hold parts of the front line.
Ukrainian officials say that, like the defenders who held out in Mariupol for weeks, fighters have taken refuge in a chemical plant in Sievierodonetsk, along with an unknown number of civilians, suggesting it may take Russia days or weeks - if at all - to seize complete control.
Capturing the Donbas has emerged as one of the Kremlin's main objectives since it failed to seize the capital, Kyiv, several weeks into the war. Days before the invasion began, President Vladimir Putin of Russia recognised the independence of two breakaway territories in Donbas, where Russia-backed separatists have fought for eight years against Kyiv.
At that time, the separatists claimed about three times as much territory as they actually controlled. Now, after almost four full months of fighting, including weeks of shelling on Sievierodonetsk alone, Russian forces seem to be verging on control of Luhansk.
But Russia faces an even more difficult battle to seize the remaining territory held by Ukraine in Donetsk, analysts say, given the heavy casualties it has suffered and strong Ukrainian resistance. That Ukrainian backbone may be stiffening further, they say, as their fighting forces are bolstered by weapons arriving from the West, although it remains unclear that those weapons can turn the tide of the conflict.
Britain's military intelligence agency said on Tuesday that Ukraine had "almost certainly" used newly delivered Harpoon missiles to strike a Russian tugboat near Snake Island, in the Black Sea, one of a series of Ukrainian strikes in the area.
The Ukrainian military said it also had destroyed an air-defence system and radar installation on Snake Island - an attack that Russia's Defence Ministry said it had thwarted.
Both sides have been testing for any weakness along a battlefront that extends from Kharkiv in the north to Mykolaiv in the south. On Wednesday, Russia pummelled Kharkiv with the most intense artillery bombardment since last month, when Ukrainian forces pushed the Russians back from the city.
At least 15 civilians were killed and 16 were wounded on Tuesday, according to Mr Oleg Sengubov, the head of the Kharkiv regional administration, accusing the Russians of artillery strikes on "residential areas where there are no military facilities".
The Kremlin, with its renewed strikes around Kharkiv, was trying to keep Ukrainian forces occupied and away from other battles, and out of range of railway lines in the region used to resupply Russian forces, according to military analysts.
Ukrainian military officials have painted a striking picture of Russia's efforts to flank Lysychansk from the east and west. In the west, Russian troops have positioned themselves to build pontoon bridges near the town of Siversk, a key strategic hub for Ukrainian supply routes, according to those officials.
And in the east, Russian reconnaissance units have tried to scout Ukrainian artillery positions in an attempt to destroy them and seize higher ground behind the city.
"We are being pressed closer to the city," said Oleksandr Voronenko, a military police officer in Lysychansk. "As long as there is a corridor through Siversk to Lysychansk, we will stand."
While Russia seems to have made gains in Donbas, Ukraine has vowed a counterattack on Russian-occupied territory in the southern Kherson region, despite the risks to civilians in the territory.
This week Ukraine's deputy prime minister Iryna Vereshchuk urged civilians to flee - even to Crimea, the peninsula seized by Russia in 2014 - rather than try to survive fighting in places where Russian forces have amassed sizeable defences.
"We know that today it is almost the only humanitarian corridor available, if it can be called that, that can be used to leave," Ms Vereshchuk said at a news conference. "So, if possible, get out of there, especially if you have children."
Russia's gains have left towns and cities as ashen husks, bombed out, deserted and often lined by freshly dug graves. Ukrainian officials have estimated that tens of thousands of civilians have been killed, and recently said as many as 100 to 200 soldiers were dying a day.
The Russian government has largely kept silent on its casualties in the course of the war, leaving families uncertain about whether their sons, brothers and spouses are dead or alive - even weeks after major, public losses, like the sinking of the warship Moskva.
The Defence Ministry, in its last casualty announcement March 25, reported 1,351 deaths. In April, Western officials estimated Russia had lost 15,000 soldiers. Last week, Ukraine put the Russian toll at 33,000. None of these figures can be corroborated independently.