Kyiv Mayor Vitali Klitschko said Tuesday that about 600,000 residents have fled the Ukrainian capital in recent weeks after Russian attacks crippled power, heating and water supplies, prompting him to urge people to temporarily leave the city amid extreme winter cold.

Air raid sirens rang out over Kyiv during an interview in which he said that around 600,000 people had heeded his call on January 9 to leave after a barrage of Russian drones and missiles cut power, water and heating to swathes of the city as temperatures plunged to -20C.

"Not everyone has a chance to leave the city, but right now the population is reduced," Klitschko told AFP, specifying that 600,000 people had moved from the capital of some 3.6 million people.

"The temperature is almost minus 20, and Putin is using it to break the resistance, to drive everyone into depression, to create tension in society," he said, referring to Russian leader Vladimir Putin.

He again urged people who had alternative accommodation to leave in order to reduce pressure on the energy network in the capital.

The Russian barrage of hundreds of drones and missiles on January 9 left half of all residential buildings in Kyiv, some 6,000 buildings, without heating.

Moscow's forces have launched several more large-scale attacks since, including just hours before the interview in an overnight strike that again saw power, heating and water knocked out for hundreds of thousands of people in Kyiv.

Long power outages have become routine since Russian forces began systematically striking Ukrainian energy facilities in 2022.

But some residents now say they have just one or two hours of power all day, if any at all.

'Fighting to survive'

AFP journalists in Kyiv have witnessed shops and restaurants closed due to the outages, out-of-order traffic lights, and public lighting shut off at night in parts of Kyiv.

"You can imagine if there is no power, no water at your home. You cannot take a shower. Your radiators are cold. The situation is very critical," the mayor said.

"We're fighting to survive, and fighting to give services to people -- heating, water, electricity," he said.

Klitschko, a former world champion boxer who has held his role since 2014, has come under fire from the presidential administration for the city's response to the attacks.

The solution to the problem, Klitschko told AFP, was to build an entirely new energy system, but this was not possible with the conflict ongoing.

He said repair work was complicated by the freezing weather conditions and constant air raid sirens that force energy engineers to shelter to avoid attacks.

"Everything right now depends on anti-missile systems" that fend off more Russian attacks, he added.