Russian forces fired more than 20 missiles at Ukraine’s capital in a predawn assault on Saturday that left at least two people dead.

Kyiv, the capital, found itself under attack for the eighth time this month as anxiety grew in Russia over a confrontation between Moscow’s military leadership and Yevgeny V. Prigozhin, the outspoken founder of the Wagner mercenary group. The leadership accuses Mr. Prigozhin of trying to mount a coup against President Vladimir V. Putin.

Serhiy Popko, the head of the Kyiv military administration, said air defenses had shot down more than 20 missiles around the capital but that falling debris had hit a high-rise building and started a blaze that destroyed three floors. In addition to the dead, 11 people were injured, he wrote on Telegram.

Just after dawn, smoke was still rising from the building as firefighters used a crane to observe damage to its 16th, 17th and 18th floors. Residents carefully stepped over the broken glass and building fragments that had scattered throughout the parking lot below.

Two women, their legs dotted with small wounds, walked out from the building. One was wrapped in a blanket; the other wore only a robe.

Residents of Kyiv had been shaken from their sleep just before 2:30 a.m. local time as air-raid sirens blared. The city’s mayor, Vitali Klitschko, reported explosions as other officials said air defenses were working and urged people to take shelter.

Volodymyr and Iryna Kuts were awakened in their apartment on the 19th floor by a crash as debris tore through the stories below.

“I don’t know how we survived,” said Mr. Kuts, 65. Their windows were blown out and smoke filled the air.

“We were just hugging thinking we would suffocate,” Ms. Kuts, 62, said. They eventually made their way down the stairs, helped by police officers.

Outside the building, dozens of residents milled around, many looking toward the charred and gaping hole ripped into its side.

Dymytro Romanov, 42, lives in a neighboring high-rise and said it was a matter of chance that his building was unscathed.

“I also live on the 18th floor,” Mr. Romanov said as he pointed toward his building. “But I got lucky.”

Emergency workers were still on the scene, helping evacuate the wounded: an older couple, a woman on a stretcher and a man walking on his own, covered in dust and debris.

Just before 6 a.m. the wail of an air-raid siren pierced the air again, sending residents racing for an underground shelter.