Two months on, Russia is still struggling to capture this small Ukrainian city

   (CNN) — It’s been nearly two months since Russian forces began their assault on the city of Severodonetsk. But despite overwhelming firepower, they still can’t dislodge determined Ukrainian resistance — nor cut the supply lines that provide the city’s remaining defenders with a drip-feed of weapons and ammunition.

The fierce Ukrainian defense of Severodonetsk, despite heavy losses, has forced the Russians to concentrate firepower on a relatively small area and held up their efforts to seize the 10% of Luhansk region they still do not control.

Russian President Vladimir Putin declared the seizure of Ukraine’s eastern Luhansk and Donetsk regions as one of the objectives of Moscow’s special military operation that began in February. For now, that operation is largely stalled; a large part of Donetsk remains beyond the Russians’ reach.

Russian forces are making modest gains — the Russian Defense Ministry said Sunday that the town of Metelkino just southeast of Severodonetsk had been taken. But the Russians’ goal of encircling the Ukrainian troops defending the twin cities of Lysychansk and Severodonetsk still appears some way off.

In a campaign lacking agility and imagination, the Russians have resorted to one principal tactic: overwhelming indirect fire against any and all Ukrainian positions, regardless of the collateral destruction.

The aim is to leave nothing standing that can be defended. The use of troops on the ground to take and hold urban areas has been less frequent and less successful.

In a video of Ukrainian special forces in the area released at the weekend, one unidentified Ukrainian soldier says: “They are throwing everything they have, all the munitions they have. It doesn’t matter for them if it’s our positions or civilian areas, they wipe everything from the face of earth and then they use artillery and then they start moving forward little by little.”

Amid intense urban combat, some 500 civilians, including dozens of children, have taken shelter in the Azot chemical plant in Severodonetsk. Unlike the Azovstal plant in Mariupol, it offers little protection below ground. Ukrainian officials say people there, who previously refused to leave, do have food supplies but can no longer be evacuated from the plant because of the intense fighting.

But as with Azovstal, the Azot plant and its immediate surroundings have become the focal point of Ukrainian resistance — frustrating Russian commanders.

According to the Institute for the Study of War (ISW) think tank in Washington, “Russian troops are likely facing mounting losses and troop and equipment degradation that will complicate attempts to renew offensive operations on other critical locations as the slow battle for Severodonetsk continues.”

Just as the defense of Mariupol drew in more than a dozen battalion tactical groups, so overcoming resistance in Severodonetsk is proving labor-intensive.

Grinding down resistance

The Ukrainians claim to have inflicted heavy losses on Russian forces in the area — in part thanks to new equipment from Western allies, including anti-tank weapons and longer-range howitzers supplied by the United States and France. On Saturday, the Ukrainian armed forces claimed that units of Russia’s 11th Separate Motorized Rifle Regiment had suffered significant losses and were “withdrawn from the area of combat operations to restore combat capability.”

However, Ukrainian supply lines are under constant attack, and it has become more difficult to ferry supplies from further west in Donetsk region along the highway to Lysychansk.

The ISW still expects that “Russian forces will likely be able to seize Severodonetsk in the coming weeks, but at the cost of concentrating most of their available forces in this small area.”

The Russians’ tactics so far suggest a campaign to grind down resistance south of the city — in places like Syrotyne — and then attack Ukrainian defenses from several directions.

Ukrainian officials say the Russians are increasingly using drones to identify their defensive positions. “The Russian military monitors the air day and night with drones, adjusts firepower, quickly adapts to our changes in defensive areas,” said Serhii Hayday, head of the Luhansk regional military administration.

Elsewhere along an active frontline that stretches for more than 1,000 kilometers (more than 620 miles), little territory is currently ceded or taken.

The Russians’ principal goals in Donbas are to take the industrial city and transport hub of Sloviansk and the town of Bakhmut, both in Donetsk — but they’ve made very limited progress towards either objective. They may also be vulnerable to Ukrainian counterattacks south and west of the city of Izium.

Southern Ukraine represents a different picture. The Russians appear to be consolidating gains won in the opening days of the war, along lines that allow them to defend a coastal belt in depth. Ukrainian counterattacks towards Kherson city have made limited progress, as the Russians are now well dug-in and show little appetite for trying to win more territory.

As UK Prime Minister Boris Johnson put it Sunday, after his second visit to Kyiv: “Time is the vital factor. Everything will depend on whether Ukraine can strengthen its ability to defend its soil faster than Russia can renew its capacity to attack.”

Brittle morale

Some of Ukraine’s best military units have been punished during the defense of Donbas. Defense Minister Oleksiy Reznikov told CNN last week that tens of thousands of Ukrainians had been killed since the Russian invasion began on February 24. Probably the vast majority have been soldiers.

The UK Defense Ministry assessed this weekend that Ukrainian forces have likely suffered desertions in recent weeks — though it believes Russian morale is much more brittle.

So, it’s not solely about getting accurate long-range weapons to Ukrainian forces but also stepping up training. Johnson is pushing a plan whereby allies develop the potential to train up to 10,000 soldiers every 120 days.

Despite their losses, and even as they deploy vintage T62 tanks in some places, Russian forces retain huge superiority in armor and combat aviation. And despite a ponderous and predictable strategy, they can continue to obliterate Ukrainian defenses. Video emerged at the weekend revealing the scale of destruction in Lyman, near Sloviansk, just as Popasna and Rubizhne further east were leveled in April.

But with an accelerated flow of weapons capable of blunting Russia’s advantage in heavy artillery and rocket systems, Ukrainian forces might yet prevent the enemy from inflicting such devastation on more towns and cities further west.