Russia launched a massive drone strike early Friday, hitting key infrastructure in western and southern Ukraine and destroying private homes and commercial buildings in Kharkiv, Ukraine’s second-largest city, Ukrainian officials said.

The BBC said it shot down 24 Shahed drones out of 40 launched by Russia.

It was the largest drone strike in recent weeks, targeting Kharkiv in the northeast, Odesa and Kherson in the south, and the Lviv region on Ukraine’s border with Poland in the west.

An Kh-59 missile was also shot down, the Air Force said.

“We understand that as winter approaches, Russian terrorists will try to do even more damage. We will respond to the enemy,” replied President Volodymyr Zelenskyy, adding that air defense had become operational in 10 regions.

Ukraine is bracing for a second winter of Russian airstrikes on its energy system, with authorities warning that the country is more vulnerable than last year because it has less backup capacity and spare equipment.

The Air Force said the newest drones were launched in several waves and flew to different regions in small groups. The air alert in some regions lasted for several hours at night.

Lviv Governor Maksym Kozytskyi said that during the shelling of his region, infrastructure objects were hit five times, but did not provide details of the damage. No casualties have been reported.

In the neighboring Ivano-Frankivsk region, a military facility was hit, Governor Svitlana Onishchuk reported.

Odesa regional governor Oleg Kiper announced the attack on the infrastructure object of the southern region.

Kharkiv Oblast Governor Oleg Synegubov said that drones hit civil infrastructure facilities and caused fires in Kharkiv and its surroundings. According to him, eight people, including two children, needed medical help due to acute stress.

Minister of Internal Affairs Ihor Klymenko said that during the shelling of the city of Kharkiv, eight private houses, a three-story building, several cars and a car workshop were damaged.