Russia pummeled Kyiv with drones and missiles overnight on Tuesday, killing at least 14 people and wounding more than 100, according to the local authorities, in the deadliest attack on the Ukrainian capital in almost a year.

It was the latest in a series of Russian air assaults that have intensified in recent weeks, dimming already fragile hopes for a cease-fire and coming as world leaders were convening for a Group of 7 summit in Canada that few believe will help bring an end to the war.

“Putin is doing this solely because he can afford to keep waging war. He wants the war to go on,” President Volodymyr Zelensky of Ukraine said in a statement from the summit, referring to President Vladimir V. Putin of Russia. The Ukrainian leader planned to press Ukraine’s allies for more support and tougher sanctions on Russia at the gathering, but President Trump, whom Mr. Zelensky was expected to meet on Tuesday, abruptly left on Monday night.

Mr. Zelensky slammed what he described as the world’s failure to deliver a strong rebuke to Russia’s assaults. “It’s a disgrace when the powerful of this world turn a blind eye to it,” he said.

The Ukrainian Air Force said the latest attack had involved 440 drones and decoys alongside 32 missiles, targeting cities across the south and west as well, including the port city of Odesa, where one resident died. The Air Force said it had intercepted most of the drones and roughly three-quarters of the missiles, although those figures could not be independently verified.

It was unclear exactly where all the 14 fatalities had occurred across the capital. Mayor Vitali Klitschko said that a 62-year-old U.S. citizen had been found dead in a house near a strike site. But Mr. Klitschko said doctors had “declared him clinically dead — biologically dead,” leaving it unclear whether the person had died because of the attack.

In Kyiv, air-raid sirens lasted for nearly 10 hours, with residents enduring an all too familiar soundtrack of the buzz of attack drones flying over neighborhoods, the staccato of heavy machine guns trying to shoot them down, and the thud of air-defense missiles trying to intercept Russian missiles.

As dawn broke, thick plumes of black smoke rose over the capital, and the acrid smell of burning hung heavy in the air. Damage was reported at more than a dozen sites across Kyiv, including a nine-story residential building outside the city center that was hollowed out by a missile strike.

On Tuesday morning, rescuers were clearing rubble from the building, which now stood with a gaping hole in one of its end sections. Amid the mangled concrete and twisted metal lay remnants of ordinary lives shattered in a split second by the strike — a pan, a kitchen glove, a half-crushed can of soda.

Using a crane, rescuers pulled a survivor from an apartment that teetered beside the collapsed section of the building. Shards of glass from shattered windows blanketed the ground, crunching under the boots of firefighters and police officers. The local authorities said that two bodies had been pulled from the rubble and warned that more people might still be trapped under the ruins.

Standing at the foot of the building, his face speckled with blood and scratches, Evgeniy Povarenkov stared into the void. He pointed to a blown-out window beside the gaping hole in the structure.

“My apartment,” he said, still struggling to process how he had survived the attack.

Mr. Povarenkov described how the explosion jolted the building at 3:45 a.m. and knocked him unconscious. When he woke up, he saw that his mother had been badly injured. He pulled her from the apartment, and rescuers rushed her to the hospital. He was now waiting to be allowed to return to pick up documents.

“They are killing us, killing the Ukrainian nation,” Mr. Povarenkov said of Russia. “And now the United States has refused to help.”

Inside the building, Mykola Leschenko was picking through the wreckage of his apartment. The blast detached the front door from its frame and he had propped it back up, through it threatened to collapse at any moment.

Mr. Leschenko said the missile had hit as he was leaving a bomb shelter in the neighborhood, thinking the attack was over. He went back to the shelter and stayed until 5 a.m. He said a friend of his lived in the building section that had collapsed in the attack. “I’m calling him now,” he said. “He doesn’t answer.”

Standing in the corridor, a half-smoked cigarette in her hand, his mother-in-law, Tetiana Berestova, said bitterly: “This is the Russian world” — a reference to the Kremlin’s vision of a civilization that is rooted in Russian language and culture, and that Moscow claims includes Ukraine.

Tuesday’s attack followed the broader pattern seen in recent weeks, with Russia launching hundreds of drones at night in an effort to overwhelm Ukraine’s air defenses, before firing missiles that are more difficult to intercept.

The United Nations said in a statement that the overnight attack was the fourth time this month that Russia had launched more than 400 drones and missiles in a single night. By comparison, Moscow launched about 550 aerial weapons during the entire month of June 2024.

Moscow says it targets only military infrastructure, and the Ukrainian authorities rarely report successful strikes on military objects. Still, because the attacks often take place in urban centers, they have resulted in numerous civilian deaths. The United Nations said that nearly “50 percent more civilians have been killed and injured in Ukraine in the first five months of 2025 than during the same period in 2024.”

The attacks have stretched Ukraine’s air defenses and exhausted Ukrainian civilians, many of whom now spend several nights a week sleeping in apartment corridors, subway stations or bomb shelters in an attempt to stay safe.

The strikes have also reinforced a widespread belief in Ukraine that Russia is not interested in a cease-fire, despite participating in negotiations that have so far yielded little beyond a limited exchange of prisoners of war and bodies of fallen soldiers.

Russian forces in the meantime are advancing across the eastern front, pushing toward the cities of Sumy, Kostiantynivka and Pokrovsk. Last month, Russia captured over 200 square miles of territory in Ukraine, more than double its gains in April and the second-highest monthly advance since the first year of the war, according to the Black Bird Group, a Finland-based research organization that tracks battlefield developments.

“Putin isn’t interested in talks, he has to conquer us,” said Tetiana Pokholovich, 63, a resident of the residential building hit by Tuesday's strike. Standing at its foot, she said her own apartment had been mostly spared, aside from shattered windows, but the impact of yet another sleepless night was etched on her tired face.

Her eyes filled with tears as she turned to go back inside. “We want peace,” she said.

Nataliia Novosolova contributed reporting.