How a Russian Barrage Evaded Ukraine’s Defenses to Wreak Deadly Chaos

For months, Ukraine’s use of powerful Western-supplied air-defense systems to repel Russian missile attacks has provided its citizens with some reassurance that a protective shield was effectively in place over big cities such as the capital, Kyiv.

On Friday, that shield partly cracked.

In one of the biggest air assaults of the war, Russia launched so many missiles that the Ukrainian defenses seem to have been overloaded. Faced with a complex barrage of different airborne weapons, the Ukrainian Air Force said it had shot down only 87 of the 122 missiles fired by Moscow, about 70 percent of the total, with all hypersonic missiles and many ballistic missiles evading interception.

Serhii Kuzan, chairman of the research group Ukrainian Center for Security and Cooperation, was blunt. “It overwhelmed Ukrainian air defenses,” he said.

To be sure, air defenses are imperfect and the magnitude of the barrage played an important part in the number of missiles to slip through. But the bombardment also showed how Russia has learned the best ways to evade Ukraine’s air defenses and hit the country hard, military experts and Ukrainian officials said. For months, Russia had stockpiled vast quantities of high-precision missiles and launched wave after wave of drones, in what appeared to be a campaign to probe Ukrainian defenses.

The attack on Friday “was very cleverly constructed,” Mr. Kuzan said. “Russia attacked with drones and ballistic and hypersonic missiles, combining them in different waves and launching them from different locations.”

Ukraine’s response became clear late Friday night, when Russia’s military said it had intercepted 13 missiles launched by Ukraine at the Russian region of Belgorod, which borders the two countries. The missile and drone attacks by Ukraine continued into Saturday, with Ukrainian news media characterizing the barrage as an answer to the previous day’s assault. Russian authorities said that at least 14 people, including two children, were killed by shelling in Belgorod on Saturday and more than 100 wounded.

In Ukraine in recent months, most missiles fired by Russia at Kyiv have been intercepted before residents even realized what was coming at them. For Ukrainian citizens away from the front line, the death and destruction wrought on Friday in cities including Kyiv, Kharkiv, Lviv and Dnipro were painful reminders of the war’s enduring threat.

Friday’s strikes killed at least 39 people, wounded about 160 others and hit critical industrial and military infrastructure as well as civilian buildings like hospitals and schools. They also raised concerns about Ukraine’s ability to withstand similar attacks in the future, as a protracted war leaves Kyiv short of critical weapons, including antiaircraft missiles, while Moscow expands its arsenal.

“It is obvious that with the stocks of missiles that the aggressor state has, they can and will continue such attacks,” Rustem Umerov, Ukraine’s defense minister, said in a social media post on Friday.

After the attack, Ukrainian officials renewed their calls on Western allies to accelerate the delivery of air-defense weapons to Kyiv. But political infighting, notably in Washington but also increasingly in Europe, has left doubts hanging over additional aid to Ukraine, including a critical $50 billion security package that Congress has repeatedly refused to pass.

During Russia’s intense air bombardment of Ukraine last winter, missiles slammed relatively easily into military and civilian infrastructure, getting past what were, at the time, meager air defenses. Many of those strikes targeted the power grid, plunging Ukrainians into cold and darkness.

In response, Ukraine’s Western allies started providing Kyiv with powerful air-defense weapons, including Patriot surface-to-air batteries, probably the most advance ground-based system available. A first Patriot battery was received around April.

Ukraine’s defenses soon improved.

In May, Ukraine managed to intercept about 83 percent of Russian missiles, according to data released by the Ukrainian Air Force. On one day, when Russia launched 51 missiles, 48 were shot down, the military said. Data compiled by Rochan Consulting, an analysis group based in Poland, showed that the high interception rate largely continued through December.

In response, Russia seems to have begun trying out different combinations of air weapons and attack routes to figure out how best to penetrate those defenses.

As part of those efforts, the Ukrainian military said, Russia has used cheap Shahed attack drones to test defenses. A month ago, Russia launched about 75 drones in an overnight assault, a “record number” at the time, according to the Ukrainian Air Force.

Yuriy Ihnat, a spokesman for the Ukrainian Air Force, said on national television this fall that the use of drones “allows the enemy to draw conclusions about the forces and means in a particular region and take this information into account when planning future attacks.”

An analysis of the trajectories of Russian air attacks, compiled by Texty, a Ukrainian publication specializing in data journalism, showed that Russian drones were often flown along a major highway in southern Ukraine — presumably because their noise blended with the sound of traffic, making them less detectable — and that they were often launched from Crimea. Sometimes, drones and missiles were fired from locations far apart, but aimed at the same target, the analysis found.

Ukrainian officials have also warned that they believe Russia has stockpiled missiles for a sustained, large-scale campaign this winter. By early November, Russia had accumulated more than 800 high-precision missiles, according to Ukraine’s military intelligence agency.

On Friday, Russia appears to have put those months of preparation into practice.

Gen. Valery Zaluzhny, Ukraine’s top commander, said on social media that the assault began with three dozen Shahed drones launched from the north and southeast in the early hours of Friday. Then, bomber jets began firing cruise missiles around 5 a.m., followed by ballistic missiles an hour later. Finally, at 6:30 a.m., Russian fighter planes launched five hypersonic Kinzhal missiles, one of the most sophisticated weapons in Russia’s arsenal.

“We saw a large number of missiles,” Mr. Ihnat, the Ukrainian Air Force spokesman, said on Friday. “The screen was red, the monitors. They were scattered all over Ukraine, flying to bypass routes. Some missiles were flying in circles before hitting their targets.”

Ukraine managed to intercept only the first wave of cruise missiles, fired around 5 a.m. The other missiles crashed into warehouses, weapons factories and residential buildings, burying people under the rubble.

The attack suggested that “the Shaheds that preceded the missiles may have distracted Ukrainian air defenses or otherwise enabled the strike,” the Institute for the Study of War, a Washington-based research group, said in an assessment.

Another possible reason some missiles evaded Ukrainian air defenses was the munitions’ use of decoys. Unverified videos posted to social media showed what appeared to be a Russian cruise missile ejecting flares, a type of decoy commonly used by combat aircraft to confuse air defenses.

Mr. Kuzan, of the Ukrainian Center for Security and Cooperation, said Russia’s attack on Friday showed that Ukraine still did not have enough equipment to repel large, coordinated barrages.

By contrast, Mr. Kuzan warned, Russia “has enough resources to do several more attacks like this one,” adding that, in his opinion, Moscow was “already preparing for the next one.”

Daria Mitiuk contributed reporting.