Russian Strategy in Ukraine Shifts After Setbacks, and a Lengthy War Looms

Ukraine’s counterattacks—including a helicopter strike inside Russian territory—and Moscow’s redeployment toward Donbas in Ukraine’s east suggest that both sides believe they can win, making it unlikely that peace talks will result in a deal anytime soon.

Russia’s “military and political strategy hasn’t changed, it remains to annihilate Ukraine,” said

Andriy Zagorodnyuk,

a former Ukrainian minister of defense who advises President

Volodymyr Zelensky’s

government. But he said, “Now, their capabilities no longer match their strategic vision.”

That could be a recipe for a prolonged conflict, increasing the stakes for both sides’ ability to raise troops and money and access weapons, ammunition and supplies.

For Ukraine, with its smaller military resources, such a shift to a lengthy conventional war heightens the need for shipments of heavy weapons such as tanks and artillery, Ukrainian officials said.

Russia’s declared shift toward trying to seize Donbas could allow it to concentrate firepower on a smaller front, shorten supply lines and make air support easier, giving Moscow a better chance at military success. It would also position Russia to try to encircle some of Ukraine’s best units, which are stationed there.

The Russian pullbacks from Kyiv, however, also allow Ukraine to redeploy additional resources to the eastern Donbas front—and to do it much faster because of shorter routes.

Ukrainian officials were initially skeptical of Russian announcements that Moscow would limit military operations near Kyiv and Chernihiv, but lengthy convoys of Russian armor began leaving these areas Thursday, and scores of villages in northern Ukraine have been retaken by Ukrainian troops.

Russia appears determined to retain a smaller, blocking force around Kyiv to threaten the Ukrainian capital and prevent a large Ukrainian redeployment to Donbas, Ukrainian officials say. But a threat of encirclement of these Russian forces, northwest or northeast of Kyiv, could still precipitate a full withdrawal toward the Belarus border in coming days, they say.

“The enemy is not fully successful in retaining the areas that it wishes to keep. Our forces are kicking them out in the northwest and northeast, pushing the enemy away from Kyiv and making another attempt at storming it impossible,” Ukrainian presidential adviser

Oleksiy Arestovych

said Friday.

Russia sent some of its best units to Kyiv and northern Ukraine. Many of them have been battered by fierce fighting, and would need considerable time to be reconstituted and prepared for redeployment, military analysts say.

U.S. officials estimate that some 10,000 soldiers out of Russia’s 190,000-strong force in Ukraine have been killed, with tens of thousands of others injured or taken prisoner. The elite 4th Guards Tank “Kantemirovskaya” Division lost 46 of its estimated 220 T-80 tanks, according to visual evidence compiled by military analysts.

Seeking to replenish its forces, Russia has been calling up reserves, sending to Ukraine troops deployed in Nagorno-Karabakh and South Ossetia as well as conscripts. Some of these troops, particularly from the Russian National Guard, which usually performs mostly internal-security duties, have refused orders to deploy to Ukraine.

British Air Marshal Edward Stringer, who headed operations for the British Defense Ministry and also helped create Britain’s military training program in Ukraine, said Russia no longer has many additional reserves to throw into new offensives.

“Most of the effective combat power is already assigned to the war,” he said. So Russian President

Vladimir Putin

“has to build some more, which is tricky without mobilizing and under sanctions, or concentrate the combat power that he has.”

Russian nationalists, dismayed by the retreat from Kyiv, have called on Mr. Putin to mobilize for all-out war.

Igor Strelkov

—a former Russian intelligence officer who led a group of Russian military veterans that seized the Ukrainian city of Slovyansk in 2014, sparking the armed conflict in Donbas—complained this week about members of the Russian National Guard refusing Ukrainian deployment and resigning.

“That’s why we need a mobilization. Submitted a resignation? Please proceed right away to the infantry company as a private. Under the convoy of your former comrades,” Mr. Strelkov wrote on his Telegram channel.

Mr. Strelkov said the retreat from Kyiv and Chernihiv was necessary given the poor execution of the Russian military plan and the threats that these forces face, especially now that spring vegetation will provide concealment for Ukrainian strike groups attacking the Russians’ rear.

“If leaving previously taken territory is inevitable anyway, it’s best to do it without the enemy annihilating your troops first,” Mr. Strelkov wrote Friday. “We will need these troops—the war will be long.”

In northeastern Ukraine, Russian forces have tried for weeks to fight their way south, past the city of Izyum in the Kharkiv region. That maneuver, if successful, could allow them to link up with troops pushing from the southeast and encircle Donbas. Much of that southeastern force is still engaged in urban battles in the besieged city of Mariupol—and could renew its push north should Mariupol fall.

Ukraine has deployed some of its best units in Donbas, which is comprised of the Donetsk and Luhansk regions. While Mariupol, a part of the Donetsk region, has been encircled, Ukraine has largely held the line to the north, including the key cities of Kramatorsk and Slovyansk.

In the Luhansk region, Russia swiftly seized rural areas in the east but hasn’t been able to take the major urban area around Severodonetsk, where the Ukrainian regional government for Luhansk is based.

Many Ukrainian officials and military analysts think the conflict is likely to drag on for months, or longer, even as Kyiv and Moscow continue peace negotiations. While these negotiators have made some progress on Ukraine abandoning its aspiration to join the North Atlantic Treaty Organization in exchange for binding security guarantees from the West and Russia, Kyiv and Moscow still remain far apart on the status of Donbas and Crimea, among other issues.

Even though Russia has a much larger population—145 million to pre-war Ukraine’s 37 million—and significantly more military equipment, time isn’t necessarily on Moscow’s side in a lengthy war of attrition.

“Military potential, as any system, is as strong as its weakest component. And Russia’s weakest component is its people. They have a lot of equipment, a lot of armor, but they have a big problem with trained personnel,” said Mr. Zagorodnyuk, the former Ukrainian defense minister.

Ukraine, which had an army of some 200,000 troops at the beginning of the war, would by contrast be able to field another force of similar size if necessary, he added. “If there is a long war, the only question is whether Ukraine will have the support of our Western partners, first of all the U.S. And if we have this support, we can outlast Russia,” he said.

Until recently, U.S. and allied weapon supplies to Ukraine were premised on estimates that Kyiv would collapse quickly, and that the war would largely be fought as an insurgency. These weapons, such as Stinger antiaircraft missiles and Javelin and NLAW antitank missiles, can be carried by one person and have been heavily used by Ukrainian troops operating as small nimble units.

Instead, Ukraine has been engaged in fighting a large-scale conventional war, using long-range artillery, tanks, air defenses and its own warplanes and combat helicopters—military assets that, while being lost daily, haven’t been replenished by the West.

That is slowly beginning to change. On Thursday, U.K. Defense Secretary Ben Wallace said a donor conference of 35 nations agreed to provide Ukraine with long-range artillery, armored vehicles, counter-battery systems and antiaircraft and coastal-defense weapons. While falling short of the tanks and combat aircraft requested by Mr. Zelensky, these supplies, if delivered quickly, would significantly improve Ukraine’s chances.

“The next three weeks will determine whether Russia’s war of attrition can succeed. If we, the West, have the sense of urgency and can provide Ukraine with what it’s been begging for, then they can break the back of the Russians while the Russians are down, and can win,” said retired Lt. Gen.

Ben Hodges,

a former commander of the U.S. Army in Europe. “But if we don’t have that sense of urgency, the Russians will have the time to regroup, to re-establish logistics, and to continue grinding down Ukrainian cities and Ukrainian armed forces.”

Write to Yaroslav Trofimov at yaroslav.trofimov@wsj.com