Russia Stumbles in Biggest Test of Its Military Force

The Russian military has faltered early in its invasion of Ukraine, as stiff resistance threatens to turn Moscow’s hopes for a swift victory into a protracted and costly war, U.S. officials and allied military experts say.

The Kremlin’s ongoing invasion represents the most formidable challenge for the Russian military since it was modernized under Gen. Valery Gerasimov, Russia’s top military officer who was appointed to his post in 2012. Yet no Ukrainian cities have been taken by the Russian military. Some of the Ukrainian Air Force and air defenses are still intact.

Western officials and analysts say that Russia’s strategy had been based on the premise that an initial barrage of missile strikes and a thrust toward Ukraine’s capital would bring about the quick collapse of President Volodymyr Zelensky’s government. Mr. Zelensky, however, remains defiant while facing long odds.

Russia holds many military advantages over Ukraine’s forces. One third of Russia’s combat power near Ukraine is still outside the country, the Pentagon says, and has yet to enter the fray. The next few days could prove pivotal, as the Russians ponder whether to take a more aggressive approach to bludgeon Mr. Zelensky’s government into submission, potentially causing more civilian casualties.

The Russian military has a prodigious array of artillery, rockets and air power. Employing these weapons, however, would only further antagonize the population that Moscow is hoping to draw into its sphere of influence and make it harder for the Kremlin to control a country of 44 million.

Since the start of the conflict, Russia has fired more than 320 missiles. Its ground forces have advanced from Belarus to within 30 kilometers of Kyiv’s city center. Russian forces have also moved swiftly from their bases in Crimea and carried out a rare amphibious landing from the Sea of Azov.

Now, the Pentagon says there are signs that Russia is resorting to more firepower, including rockets, in its attempt to take Chernihiv, a city 150 kilometers northeast of Kyiv.

Mick Ryan, a retired Australian Army major general who has studied advanced warfare, says Russia’s failure so far to achieve decisive gains and its potential depletion of precision-munition supplies “probably will force them to use older weapons that are less precise and more deadly.”

“In the next 72 hours I expect greater lethality on the battlefield,” he added.

Russian soldiers near Armiansk, Crimea, on Friday heading toward Ukraine. PHOTO: STRINGER/SHUTTERSTOCK

Western analysts say that there are few parallels between Russia’s approach so far in Ukraine and how it would face off against a NATO force, where mass firepower would be used from the outset and the potential use of nuclear weapons could also be threatened.

The Russian military has improved considerably since its wars to subdue insurgents in Chechnya, which lasted until 2000, and intervention eight years later in Georgia, which succeeded in securing two breakaway regions.

Russia’s operations since then had been limited and sometimes were carried out in areas where there was a reservoir of support. In 2014, the Russians quietly infiltrated Crimea with special forces, naval infantry and intelligence operatives and secured the peninsula with nary a shot. That same year, Russia intervened in the Donbas region in southeast Ukraine and marshaled a proxy force of separatists.

Russia’s 2015 intervention in Syria to buttress Syrian President Bashar al-Assad showcased its air power and long-range missile capability. In contrast to the invasion of Ukraine, however, the Syria operation didn’t include the deployment of a large number of Russian ground forces or combat against an organized army.

“This isn’t the small, handpicked Syria task force that was lavished with support and made relatively few mistakes,” said Dara Massicot, an expert on the Russian military at the Rand Corporation, referring to Russia’s attack on Ukraine. “A force of this size is too large to hide readiness and personnel problems within the Russian military.”

Syrian President Bashar al-Assad meeting with Russian President Vladimir Putin in Moscow in October 2015. PHOTO: ALEXEI DRUZHININ/ZUMA PRESS

Ukraine’s forces have their problems too. Mr. Zelensky’s reluctance to order a general mobilization until late last week delayed the call-up of reservists and consequently the movement of some units into defensive positions, said Phillip Karber of the Potomac Foundation, a policy center.

The longstanding U.S. policy of modulating the supply of arms to Ukraine so as not to provoke Russia has also affected the country’s military capability. Stinger antiaircraft systems weren’t sent to Ukraine until January when the Biden administration approved a request by Latvia and Lithuania to provide the U.S.-made systems from their arsenals. The U.S. has since opted to send antiaircraft missiles from its own inventory. Experts say, however, that it takes time to distribute the weapons and train Ukrainian forces in how to use them. The U.S. hasn’t outfitted the Ukrainians with antiship missiles.

The Ukrainian forces have benefited from the U.S., British and other allied training, however, as well as U.S. intelligence about Russia military moves. The Ukrainians have also been adept at moving their surface-to-air systems and turning them off at times to make them harder to be targeted by the Russians, Western analysts say. As a result, Russia has yet to achieve air superiority in the country.

A senior U.S. defense official said Sunday that the Russians have been frustrated by the slow pace of their offensive but will try to adjust their strategy and tactics in the face of setbacks. “To some degree, they’ve done it to themselves in terms of their fuel and logistics and sustainment,” the official said. “We would expect them to learn from these issues and adapt to them and try to overcome them.”

James Hackett, Senior Fellow for Defense and Military Analysis at the International Institute for Strategic Studies, a think tank in London, noted that Russia still retains advantages in personnel and equipment, though movement could now be more difficult than before since bridges have been destroyed and the Ukrainians have had time to better prepare defenses.

Watch Ukraine Fuel Depot Near Kyiv in Flames Amid Russian Shelling

Footage shows plumes of black smoke rising from a fuel depot in Vasylkiv, south of Kyiv, as Russian forces targeted airfields and other strategic facilities in Ukraine during the night. Photo: Alisa Yakubovych/Shutterstock

The course of the conflict, analysts say, will now turn on whether Ukraine can hold Kyiv and what kind of guerrilla battle the Ukrainians can maintain in the longer run.

Jack Watling, an expert on land warfare at the Royal United Services Institute, a British defense think tank, says that his analysis before Russia’s invasion had been that Ukraine’s conventional forces would hold out for 10 days before shifting to more unconventional resistance warfare.

Previous conflicts, Mr. Watling said, have shown that “the Russians always take more military losses than they should.” But a question is how much public support Mr. Putin will have at home, as the war drags on and Russian soldiers die.

Moscow’s hope, he said, had been to avoid this prospect by planning a “shock and awe” demonstration that involved rapid advances and the seizure of a few key objectives in the hope the Zelensky government would quickly surrender or flee.

“That failed,” he said.

Write to Michael R. Gordon at michael.gordon@wsj.com, Max Colchester at max.colchester@wsj.com and Daniel Michaels at daniel.michaels@wsj.com

Corrections & Amplifications

Gen. Valery Gerasimov is Russia’s top military officer. An earlier version of this article incorrectly spelled his last name as Gerisimov. (Corrected on Feb. 27.)