Ukraine warned on Tuesday of an emerging “critical” risk to its power grid after President Volodymyr Zelensky said that repeated Russian bombardments had destroyed one-third of the country's power facilities as winter approaches.

That warning came as Russian forces claimed to have retaken territory from Ukrainian troops in the eastern Kharkiv region, Moscow's first announced capture of a village there since being nearly entirely pushed out of the region last month.

At the same time, Russian attacks rocked energy facilities in Kyiv and urban centres across the country, causing blackouts and disrupting water supplies, just one day after the capital was bombarded with a swarm of suicide drones.

“The situation is critical now across the country because our regions are dependent on one another ... it's necessary for the whole country to prepare for electricity, water and heating outages,” Kyrylo Tymoshenko, the deputy head of the Ukrainian president's office, told Ukrainian television.

The strikes in the early hours of Tuesday hit Kyiv, Kharkiv in the east, Mykolaiv in the south and central regions of Dnipro and Zhytomyr, where officials said hospitals were running on backup generators.

Drones also bombarded Kyiv on Monday leaving five dead, officials said, in what the presidency described as an attack of desperation.

It was the second Monday in a row that Russia launched punitive strikes which military observers have said appear to be Moscow's response to battlefield losses.

Zelensky described the repeated targeting of energy infrastructure as “another kind of Russian terrorist attack”.

“Since October 10, 30 per cent of Ukraine's power stations have been destroyed, causing massive blackouts across the country,” the Ukrainian leader said on Twitter.

He said the attack meant that there was “no space left for negotiations with [President Vladimir] Putin's regime”.

Hospitals on backup power

Many towns and cities in the Zhytomyr region west of Kyiv and parts of the city of Dnipro in central Ukraine were without electricity, while power was restored to the southern city of Mykolaiv after strikes overnight.

“Now the city is cut off from electricity and water supplies. Hospitals are working on backup power,” the mayor of Zhytomyr, Sergiy Sukhomlyn, said in a statement online.

In the northeast meanwhile, Ukraine's second-largest city of Kharkiv some 40 kilometres from the border with Russia was hit with eight missiles, the regional governor said.

In Kyiv, meanwhile, the DETK energy provider said its staff were “doing their best to restore electricity supply after the destruction of a critical infrastructure facility in Kyiv city.”

The mayor Vitali Klitschko said three people had been killed in Tuesday's strikes.

Zelensky earlier said the fresh wave of nationwide strikes — which he said had damaged a residential building and flower market in Mykolaiv — was a Russian attempt to “terrorise and kill civilians”.

Kremlin denies Iran drone use

Following the wave of kamikaze drone attacks against Kyiv on Monday, Foreign Minister Dmytro Kuleba demanded EU sanctions on Iran, accusing Tehran of providing Russia with drones.

The Kremlin said on Tuesday it has no knowledge of its army using Iranian drones in Ukraine.

“Russian tech is being used,” Kremlin spokesman Dmitry Peskov said, referring other questions to the defence ministry.

The defence ministry did however confirm strikes on energy facilities over the past 24 hours, saying it had used long-range and precision weapons.

Iran has denied exporting any weapons to either side, but the United States warned it would take action against companies and nations working with Tehran's drone programme following the strikes in Kyiv.

Western officials however said it was “increasingly evident that Russia is pursuing a deliberate strategy of trying to destroy heating, electrical networks” and that Iranian drones were playing an “increasingly significant role” in the conflict.

Senior presidential aide Mykhaylo Podolyak meanwhile called for Russia to be excluded from the upcoming G20 summit.

With fighting ongoing across a sprawling frontline in east and southern Ukraine, its military said that over the past 24 hours it had shot down 38 Iranian-made Shahed-136 unmanned aerial vehicles.

Separately on Tuesday, Russian investigators said initial indications suggest that the crash of a military plane into a residential building near Ukraine was due to a technical malfunction.

Investigators said they were questioning the pilots of the Sukhoi Su-34, who managed to parachute out of the plane before it crashed on Monday evening into the nine-storey building, engulfing it in flames.