Overnight drone attacks target Kyiv and two other regions of Ukraine.

KYIV, Ukraine — Explosions rang out before dawn on Monday in Kyiv and in other Ukrainian cities as officials said that Russia had launched another drone attack targeting power plants and other key infrastructure.

The Ukrainian Air Force said that it had shot down 20 of 35 drones that Russia had launched, though those that evaded air defenses had hit power plants, electrical systems and other civilian targets.

At least four loud explosions were heard in the capital, Kyiv, where residents rushed to take shelter. While most of the drones that flew into the airspace over the city were shot down by Ukrainian air defenses, officials said, those that made it through struck an electrical power plant, causing additional power outages in Kyiv, which has already been subject to continuous rolling blackouts because of Russian strikes.

“There is damage,” Kyiv’s mayor, Vitali Klitschko, said in a statement. “Energy and heating engineers are working to quickly stabilize the situation with energy and heat supply.”

By the afternoon, Mr. Klitschko said that heat had been restored to all but 3 percent of the two million people still living in the city.

As an aerial battle between Russian drones and Ukrainian fighter jets and air defense missiles was heard in the skies above the capital overnight, officials in two other regions in central and southern Ukraine, Dnipropetrovsk and Mykolaiv, also reported drones overhead late Sunday and early Monday.

The drones used in Monday’s attacks were from a new batch of Iranian-made Shaheds received by Russia, President Volodymyr Zelensky said. He cited those details in an address to European leaders gathered in Latvia in which he urged more support for Ukrainian air defenses. Although Iran has officially denied supplying Russia with the weapons since the invasion of Ukraine, U.S. officials have said that the first shipment was delivered in August.

By around 5 a.m., the authorities had lifted the air-raid alert for all provinces in Ukraine except for Kyiv and the surrounding region.

Russia has launched waves of missile and drone attacks at Ukrainian electrical power plants, substations and transmission lines since October, in what military analysts say is an effort to plunge the country into darkness and cold as winter sets in. In the past week, the attacks appear to be happening in the darkness as Russian forces try to evade Ukrainian defenses.

The latest attack began late on Sunday, shortly before midnight. Vitaliy Kim, the regional governor of Mykolaiv, posted on Telegram that Iranian-made Shahed drones used by Russia were flying toward the area. “We have mopeds,” Mr. Kim wrote, using the nickname Ukrainians have adopted for the small, buzzing engine that powers the drones.

By morning, however, there were no reports that the drones had struck targets in the Mykolaiv region, which is in southern Ukraine.

Oleksiy Kuleba, the military governor of the Kyiv region, the administrative district around the capital, said that drones had hit “infrastructure objects and private houses.” Three people were wounded in the strikes, according to the regional police.

To the south of Kyiv, along the banks of the Dnipro River, more drones flew into towns and cities in the Dnipropetrovsk region, where the military administrator, Valentyn Reznichenko, said that air defenses had shot down two Shaheds. A rocket attack in the region cut electrical power to water pumps, depriving several villages of running water, Mr. Reznichenko said.

Ukraine’s national nuclear power company, Energoatom, said that one of the Iranian drones had flown over the South Ukraine Nuclear Power Plant, which lies about 70 miles north of the city of Mykolaiv, shortly after midnight. In a statement, the company called it “an absolutely unacceptable violation of nuclear and radiation safety.”

Maria Varenikova contributed reporting.