Russia fired a combined 100 missiles and drones at Ukraine overnight in a barrage that targeted energy sites across the country, Ukrainian officials said on Saturday.

Russia has launched dozens of aerial attacks at Ukraine's power facilities throughout the war, causing significant damage and energy shortages as Ukraine's stretched air defences struggle to repel the waves of drones and missiles.

"The enemy launched 53 missiles of various types and 47 attack drones," the air force said, adding that it shot down 35 of the missiles and all but one of the drones.

Two thermal power plants were damaged in the attack, the DTEK operator said, without specifying where they were located.

"It was another extremely difficult night for the Ukrainian energy sector. The enemy struck two of our thermal power plants. The equipment was seriously damaged," the company said in a statement on Telegram.

It was the sixth major attack on DTEK thermal power plants since mid-March, it added.

Ukraine's Energy Minister German Galushchenko said Russia had targeted sites in five regions -- Donetsk, Dnipropetrovsk, Kirovograd, Ivano-Frankivsk and Zaporizhzhia -- stretching from near the eastern frontlines to Ukraine's west, which borders the EU.

The ministry warned that power restrictions were likely on Saturday evening as a result of the attacks.

President Volodymyr Zelensky said Moscow was trying to "exploit" a lack of "determination" among Ukraine's key Western backers and repeated his call for more air defence systems.

"Russia's main goal is to normalise terror, to exploit the lack of sufficient air defence and determination of Ukraine's partners," he said in a social media post.

"This is a test of humanity and determination for the free world. Either we pass this test together, or the world will plunge into even greater destabilisation and chaos," he added.

In a daily briefing, Russia's defence ministry said it had launched a "group strike with long-range... precision weapons against Ukrainian energy facilities that support the work of enterprises of the military-industrial complex."

It said the strikes were a "response to attempts by the Kyiv regime to damage Russian energy and transport facilities."

Ukraine has hit several Russian oil depots and refineries in drone strikes over recent months -- something Kyiv says is fair retribution for Moscow's own aerial attacks.

Separately on Saturday, Kharkiv governor Oleg Synegubov said rescuers pulled two more bodies from the rubble of a major missile strike that hit Kharkiv city in the early hours of Friday, taking the number of those killed to nine.