Russian forces have unleashed a major attack on Ukraine in the early hours today, with multiple ballistic missiles targeting the capital Kyiv.

At least five people were killed and 23 have been injured in the strikes, Kyiv mayor Vitali Klitschko said, as witnesses reported more than a dozen explosions.

Poland said it was activating a range of defensive measures in response to the strikes unfolding across the border, describing them as "preventive military aviation operations".

A children’s hospital in Kyiv was struck in the attack, Klitschko said, while people were trapped in one destroyed residential building and fires broke out in multiple locations.

The attack comes hours after president Vladimir Putin admitted that Ukrainian attacks were causing Russia harm, in statements made on Wednesday.

"Of course, such attacks have not caused, and could not cause, critical consequences. However, they do inflict damage; this is obvious, and we fully understand and acknowledge it," he told a conference of ministers and business leaders on the economy.

Ukraine has upped its long-range attacks on critical energy infrastructure over the last few months.

Drone crashes in Romanian territory during Russian attack on Ukraine

A drone has crashed into Romanian national territory during a Russian attack on neighbouring Ukraine, the Romanian defence ministry said this morning.

The drone crashed into an uninhabited area of the Romanian county of Tulcea, the ministry said.

Watch: Zelensky condemns Russian ‘terror’ after deadly strikes across Ukraine

Poland starts preventive military aviation operations as Russia hits Ukraine

Poland has launched preventive military aviation operations to protect its airspace amid Russian strikes on Ukraine in the early hours today, the Polish army said in a post on X.

Russia launched ballistic missiles on the Ukrainian capital of Kyiv in the early hours today, killing at least five people.

Major Russian attack on Ukraine kills five and injures 23

At least five people were killed and 23 have been injured in Russian ballistic missiles strikes on Kyiv in the early hours today, mayor Vitali Klitschko said.

The attack has damaged buildings and left parts of the Ukrainian capital without power. A fire broke out after Russia attacked the upper floors of a nine-story residential building, Klitschko said, and people were trapped in another place as Moscow hit non-residential and apartment facilities, warehouses and a children's hospital.

A Reuters witness reported hearing more than a dozen explosions.

In the region surrounding the Ukrainian capital, another person was killed, a local official said separately on Telegram.

The drones that the UK supplies Ukraine following Russia’s threat

Russia has warned of “consequences” following reports that British-built drones were deployed to hit targets on its mainland for the first time.

Ukrainian army sources told The Times that drones made by two British companies have been used in the past six months to attack targets including oil refineries in Volgograd and near Moscow and logistics hubs.

Russia’s embassy to the UK said in a statement on Monday that the reports “confirm that London is deliberately opting for an escalation of the Ukraine crisis” and accused Britain of “seeking to contain Russia and inflict maximum damage on it by proxy”.

Moscow warehouse burns as Ukraine drone crews prepare to strike again

A massive retail logistics centre on the outskirts of Moscow remained in flames on Sunday morning following an overnight strike by waves of Ukrainian drones, sending thick dark smoke into the sky.

Hundreds of miles from the scene, Ukrainian drone operators had barely paused after their night operations before preparing for another attack.

Watch: UK minister hits back after Russia threat over Ukraine’s ‘use of British drones’ in record attacks

Ukraine's parliament approves Yevhenii Khmara as new defence minister

Ukraine's parliament approved the appointment of Yevhenii Khmara as new defence minister on Wednesday.

President Volodymyr Zelenskiy nominated Khmara, whom he had earlier appointed as acting minister, after the ousting of Mykhailo Fedorov in July.

The appointment was backed by 312 lawmakers, with 226 needed for a majority.