By Marc Santora and Andrés R. Martínez

KYIV – Explosions echoed across Ukraine’s capital for hours before dawn Sunday (28) as air defence teams raced to combat the largest swarm of Russian attack drones targeting Kyiv since the war began more than 15 months ago.

The Ukrainian air force said it had shot down 52 out of 54 Iranian-made Shahed-136 drones aimed at targets in central Ukraine, describing the number launched as a record. More than 40 drones were intercepted over the capital, where city officials said at least one person had been killed and another injured, probably by falling debris.

As Ukraine draws closer to launching a counteroffensive aimed at reclaiming land lost in the first months of the war, Moscow has stepped up its assaults on Kyiv. The capital has been attacked 14 times this month by waves of Russian drones, cruise missiles and sophisticated ballistic missiles.

“This was the largest-ever drone attack on the capital since the beginning of the full-scale invasion, particularly using Shahed loitering munitions,” the Kyiv military administration said in a statement.

Ukraine’s complex air defence network has become adept at intercepting the Russian barrages, often shooting down the majority of the dozens of drones and missiles. The arrival this spring of the American-made Patriot system, the most advanced US ground-based air-defence system, has given it an added layer of protection. This month Ukrainian air defences managed for the first time to shoot down some of the most sophisticated conventional weapons in Russia’s arsenal, hypersonic Kinzhal missiles, according to Ukrainian and US officials.

Although nearly every assault on Kyiv in May has been thwarted, the attack Sunday was the first to result in the loss of life.

One person died and another was hospitalized after debris from a downed drone hit a seven-story non-residential building, the Kyiv military administration said in a statement. It said the roof of a shopping mall caught fire and a warehouse was set ablaze.

President Volodymyr Zelenskyy of Ukraine praised the work of Ukraine’s air defence forces, calling them heroes.

“Every time you shoot down enemy drones and missiles, lives are saved,” he wrote in a statement on the Telegram messaging app.

The assault on the capital came as Ukrainians prepared to mark the city’s founding 1,541 years ago, a holiday traditionally celebrated on the last Sunday in May.

“The history of Ukraine is a long-standing irritant for complex Russians,” Andriy Yermak, a senior adviser to Zelenskyy, said after the assault, vowing revenge.

Mykola Oleshchuk, the commander of the Ukrainian air force, said the “record number” of drones aimed at Kyiv were “gifts” from Russia on Kyiv Day but that air defence teams working through the night had probably saved hundreds of lives by ensuring “only fragments” remained by the time the assault ended.

Ukrainian officials were quick to note that Russia has targeted the capital since the first days of the war, when they hoped to quickly seize Kyiv. The intensity of the assaults has ebbed and flowed — with Ukrainian officials saying that Russia is constantly trying to adapt its tactics.

In the latest attack, air alarms sounded in Kyiv around 1 a.m. on Sunday as the first wave of Shahed-136 drones streaming toward the city was detected.

“The routes of these aircraft were somewhat unconventional,” Natalia Humeniuk, the spokesperson for Ukraine’s southern command, said in an appearance on national television.

“They tried to bypass the southern air defense as much as possible, as evidenced by the fact that they flew mainly over the temporarily occupied territories and then dispersed across Ukraine,” she added, saying that the drones had hugged riverbeds in an attempt to evade radar.

The Ukrainian air force has explained how missiles and drones become less visible on radar the closer they press to the ground, which is one reason it is hard to shoot them down outside the Kyiv city limits.

Ukraine’s most sophisticated air-defence systems like the Patriot — which employs interceptor missiles that cost $4 million per shot — are largely reserved for countering Moscow’s most sophisticated missiles. To counter the Iranian-made drones Russia has been launching, Ukraine has tended to rely on less expensive weapons such as anti-aircraft guns and Stinger missiles.

Around 2 a.m., the skies above Kyiv lit up with tracer fire as the Ukrainian air defence teams took aim at the drones over the heart of the city.

While the drones themselves, with their distinctive triangular wing design, were often not immediately visible to civilians watching the battle in the sky, when the Ukrainians found their target, the resulting explosion looked like a fireworks display.

For nearly five hours, explosions echoed across the capital until the last drone disappeared from Ukrainian radar.

Here’s what else is happening in Ukraine:

— Front-line strikes: Russian attacks on towns and cities closer to the front line continued. Ukrainian officials said Russian shelling of the city of Kherson in southern Ukraine injured at least one person. Russian fire killed at least one person in the town of Kostiantynivka in eastern Ukraine, the officials said. Nearly two dozen villages near the front in the southern Zaporizhzhia region were hit in artillery attacks, injuring at least four civilians, local officials said. Russia also continued to shell towns and cities close to the border, killing two people in the Kharkiv region, local officials said.

— Dnipro death toll: Local officials said the death toll from a Russian missile strike on a medical facility in Dnipro on Friday has climbed to four. Authorities initially expressed hopes that people still listed as missing might be found alive.

“The three people who went missing during the missile attack on Dnipro have been found,” the Dnipro military administration said in a statement Sunday. “Unfortunately, they have been killed.”

A 56-year-old doctor, a 64-year-old employee of the damaged medical facility and a 57-year-old employee of a neighbouring veterinary clinic were among the victims.

— Bakhmut: Combat has largely subsided in the city of Bakhmut in eastern Ukraine, with only one clash reported over the past 24 hours, Serhiy Cherevaty, a spokesperson for Ukraine’s eastern forces, said Sunday on national television.

Russia now controls the shattered city after a bloody months-long battle, and the Wagner mercenary group — whose fighters led much of the assault — appears to be following through on a pledge by its founder, Yevgeny Prigozhin, to withdraw from there. Cherevaty said Russia was “rotating its troops, replacing Wagner” fighters with other units. That echoed an assessment from Britain’s defence intelligence agency on Saturday.

Ukrainian officials have said Kyiv’s forces had recaptured land on the northern and southern outskirts of Bakhmut. But Hanna Maliar, Ukraine’s deputy minister of defence, said Saturday that Ukraine had halted combat operations there for now.

-New York Times