LVIV, Ukraine—In late February, Russian President Vladimir Putin unleashed a military offensive designed to swiftly outmaneuver Ukraine’s defenders, oust the country’s government and win control over his smaller neighbor. Ten days later, Mr. Putin’s armies are struggling to gain momentum.
Combat-hardened Ukrainian troops, armed with weapons from the U.S., Britain and elsewhere, have managed to slow and in some cases halt Russian advances by taking advantage of strong morale, a deep, home-team knowledge of the battlefield and Russian shortcomings in logistics and tactics.
Ukraine’s military, which has fought Russia and Russian-backed forces since 2014, when Moscow seized the Crimean Peninsula and fomented war in the country’s eastern Donbas region, had long prepared for a wider conflict.
“The armed forces of Ukraine are now, at least on the European continent, the only armed forces that have permanent eight-year combat experience,” said Yurii Biriukov, a former adviser to the Ukrainian president. “Now here is the result.”
Russian troops have advanced from Ukraine’s south, taking the port city of Kherson. In the north, Russia’s forces have made territorial gains but failed to take the key cities of Kharkhiv and the capital, Kyiv, having met fierce Ukrainian resistance.
Ukrainian troops were able to position themselves to ambush Russian columns along some of the main invasion routes and pick off armored vehicles and trucks hauling gas and other supplies, delaying their advance, said Nick Reynolds, an analyst at London’s Royal United Services Institute think tank.
Ukraine’s military said Russia has lost 269 tanks and nearly a thousand armored personnel vehicles since the war’s start. U.S.-made Javelin and U.K.-designed NLAW antitank weapons have been widely distributed among Ukrainian forces. Kyiv hasn’t disclosed its own military losses.
The antitank weapons and deliveries of U.S.-made Stinger anti-air missiles are strengthening Ukraine’s defenses. Kyiv also has released videos it says depict strikes on Russian armored vehicles, missiles systems and fuel trucks conducted by Turkish-made armed drones.
Shipments of Western arms have continued with convoys bringing them in overland across Ukraine’s western borders.
Facing a better-armed Russian force, Ukraine has chosen to fall back to cities, defending from within, rather than chance facing Russian tanks and aircraft in the open, making Moscow’s work harder. “Clearing military units out of cities is just a long, slow, laborious process,” Mr. Reynolds said.
Andriy Zagorodnyuk, a former defense minister now at a Kyiv think tank, said the Ukrainian special forces, Pentagon-funded and -trained since 2015, had engaged in efforts to demoralize the enemy, assaulting Russian convoys and striking Russian camps at night. “They attack when they’re least expected,” he said.
Ukrainian special forces also have been instrumental in holding off Russian advances north of Kyiv, and in counterattacks that have prevented Russia from consolidating gains.
“Going deep into our territory, Russian troops are stretched and lose contact with their command,” said Yurii Kochevenko, an officer with Ukraine’s 95th Airborne Assault Brigade. “Their logistics are disrupted. They have great difficulties with the supply of fuel, with the delivery of ammunition. They abandon their equipment and scatter in all directions.”
Ukrainian servicemen took cover during shelling in Gorenka, on the outskirts of Kyiv on Friday. PHOTO: MANU BRABO FOR THE WALL STREET JOURNAL
Before the invasion, the Kremlin predicted a friendly reception from locals in Ukraine, and mass desertions from the Ukrainian army into Russian ranks. The Russian line was essentially that Ukrainian people were pro-Russian but held hostage by a U.S.-backed government opposed to Moscow.
As a result, Russia appears to have invaded Ukraine with a much smaller force than it needed, said Seth Jones, a director at the Center for Strategic and International Studies, in Washington.
Mr. Jones said Russia has mobilized about 190,000 troops for its operations in Ukraine to subdue a population of more than 40 million. France had a similar population when Nazi Germany invaded in 1939 with a force of three million.
A second mistake, Mr. Jones said, is that Russia has failed to block supply routes that are feeding Ukraine’s defense with Western antiaircraft and antitank weapons. “It’s a huge military blunder that a ton of stuff is still coming in from the West,” Mr. Jones said.
These supplies and tens of thousands of volunteers have continued to flow overland lately through the border with Poland, with the western city of Lviv serving as a supply hub.
The tide of arms underlines Ukraine’s desperate need, despite its foe’s stumbles.
“This does not mean that the Russian army has lost its combat effectiveness,” Mr. Kochevenko said. “They are still able to threaten Ukraine. But we will fight to the last drop of blood. Probably this is our main advantage.”
Local residents worked with members of the Kyiv Territorial Defense to build fortifications near a metro station on Friday. PHOTO: CHRISTOPHER OCCHICONE FOR THE WALL STREET JOURNAL
At the outset of the invasion, many foreign military observers warned that Russia’s vastly larger air force, and Ukraine’s outdated air defense systems, would allow it to take control of the skies in the early hours of the offensive. That didn’t happen.
At least some of Ukraine’s ground-based S-300 antiaircraft missile systems are still working and able to destroy Russian warplanes and inbound missiles. Ukraine’s own air force is also still flying and conducting operations against Russian forces on the ground.
“We thought that our air defense would be suppressed quite quickly, but it’s still working,” Mr. Zagorodnyuk said.
As a result, he said, Russia appears to be holding back on its use of aviation, despite having amassed a force of hundreds of jet fighters within striking distance of Ukraine before the invasion started. “They rely mainly on missile strikes, which are less risky” for the attackers, Mr. Zagorodnyuk said.
On Saturday, Mr. Putin asserted that Russia had “practically completed” destroying Ukraine’s air force and air defenses.
Ukraine’s military said it shot down an Su-34 fighter-bomber Saturday as it moved to attack the northern city of Chernihiv. The plane crashed in the city and ordnance disposal experts removed three unexploded bombs from the wreckage.
In total, from the start of the invasion through Sunday, Ukraine said it had downed 92 Russian planes and helicopters. On Saturday, Oryx, a blog that verifies destroyed military equipment via open-source imagery and intelligence, tweeted that Russia had lost three airplanes, two helicopters and a drone in the previous 26 hours.
Douglas Barrie, senior fellow for military aerospace at the International Institute for Strategic Studies in London, said Russian aircraft still use unguided bombs and rocket pods, so pilots tend to fly at a lower altitude to try to increase their chances of hitting a target.
“This also makes them more vulnerable to being shot down,” Mr. Barrie said.