At least eight people were killed and 10 others wounded when two Russian airstrikes hit Ukraine's second-largest city Kharkiv on Saturday, regional officials confirmed.

Ukraine's national police said the attack was launched by drones, while regional officials said Russian forces used missiles and bombs. The police and local authorities published pictures of fires that had broken out on city streets and next to buildings.

"As of this morning, there are 6 dead and 10 wounded as a result of the night strike on Shevchenkivskyi district," Kharkiv Mayor Ihor Terekhov said on the Telegram messaging app. Later the death toll rose to eight.

"The attack hit residential areas – at least nine high-rise buildings, three dormitories, a number of administrative buildings, a shop, a petrol station, a service station and cars were damaged," he said.

The strike occurred just after midnight, news reports said.

"Overnight Russia launched another attack against Kharkiv – Ukraine's 2nd largest city – killing 6 civilians, injuring others & damaging homes & schools," U.S. Ambassador Bridget A. Brink said on X social network.

"There is not a second to lose to support Ukraine's fight to defend its people from such horrific and unprovoked attacks," she added.

A new attack took place later Saturday and Terekhov said at least one person was killed.

"There is information about one death as a result of a strike on a residential area of the city. There are also injuries," Terekhov said on Telegram.

Kharkiv, in Ukraine's northeast, has been a frequent Russian target, with attacks intensifying in recent weeks. On Wednesday, a drone attack on the city killed four people and badly damaged apartment blocks.

President Volodymyr Zelenskyy's chief of Staff, Andriy Yermak, told the news outlet Politico in an interview published Thursday, that he saw Kharkiv as the most likely target for any new Russian offensive in May or June.

Kharkiv regional Gov. Oleh Synehubov reported a strike on a residential building and a missile attack on a village north of Kharkiv city. No casualties were reported in either incident.

Air raid alerts remained in effect for Kharkiv and most of the country, including the capital Kyiv, for several hours after the strikes.

Ukraine's military said on Facebook its air defenses destroyed 28 of 32 drones and three of six missiles launched by Russia.