Russia launched a massive attack on several Ukrainian cities overnight on Monday, President Volodymyr Zelensky has said, a day after he warned of strikes over the Christmas period.

At least three people were killed, according to Ukrainian officials, including a four-year-old child, while energy infrastructure was also targeted, leaving several regions without power.

Russia launched more than 600 drones and 30 missiles, according to Ukraine. Zelensky said people simply want to be with their families, at home, and safe in the run-up to Christmas, and said the strikes sent an extremely clear signal about Russia's priorities despite ongoing peace talks.

He added: Putin still cannot accept that he must stop killing. And that means that the world is not putting enough pressure on Russia.

Confirming a child's death in the central Zhytomyr region, local official Vitaly Bunechko said: She was taken to hospital; doctors fought for her life but could not save her in the end. Five others were injured in the strike, he added.

Meanwhile, a 76-year-old woman was killed and three people injured when a house in the Kyiv region was struck, according to Ukraine's state emergencies service. An attack in Khmelnytskyy, western Ukraine, killed a 72-year-old, regional administration head Serhiy Tyurin said.

Polish fighter jets were scrambled in response to missiles and drones targeting western Ukraine. The Russian defense ministry said it had targeted energy facilities and other transport infrastructure, according to Russian state news agency Tass.

Meanwhile, Ukraine reportedly struck a petrochemical plant in Stravropol, southern Russia. Videos shared by Russian media channels online showed large flames rising from the direction of the plant. The region's governor, Vladimir Vladimirov, said a Ukrainian drone hit the plant and sparked a fire. No casualties were reported, and residential buildings were left undamaged.

With temperatures expected to fall to as low as -7C on Wednesday, Ukraine's energy operator warned of emergency power shutdowns in all regions and urged people to use energy sparingly. Acting energy minister Artem Nekrasov said it was the ninth large attack on Ukraine's energy system this year, and that supply in the Rivne, Ternopil and Khmelnytsky regions has been almost completely lost.

The main focus of Russian attacks in recent days has been the southern port city of Odesa, which comes after Vladimir Putin threatened to sever Ukraine's access to the Black Sea.

The Tuesday morning attack punctured a period of relative calm in the capital Kyiv, where it has been weeks since Shahed drones have been spotted flying low overhead. Many suspect this attack is linked to the killing of a top Russian general after a car bomb exploded in Moscow.

According to Zelensky, the US proposed a Christmas truce, but Russia rejected the idea. He said he received a progress report on diplomatic talks on Tuesday morning, with several draft documents prepared, including a framework to end the war and future security guarantees for Ukraine.