KYIV: Russia fired dozens of missiles at cities across Ukraine on Monday in a massive barrage that killed at least 24 people and smashed into a children's hospital in Kyiv, trapping victims under the rubble, officials said.

Dozens of volunteers, doctors and rescue workers were digging through debris of a part of Okhmatdyt paediatric hospital in a desperate search for survivors after the rare day-time bombardment.

First responders ran for cover when sirens and a blast sounded hours after the initial strikes that hit as Ukraine struggles to protect itself from Russian aerial attacks.

President Volodymyr Zelensky said Russian forces fired more than 40 missiles at least five major civilian hubs mainly in the south and east of the country, as well as Kyiv.

The attack came as Zelensky visited Warsaw before heading to the NATO summit in Washington, where he was expected to appeal for more military support from the country's allies.

AFP reporters at the scene of the attacks heard air raid sirens and explosions ring out as the missiles crashed into the capital and debris from downed projectiles rained down over the city.

Natalia Svidler, 40, was in the hospital at the time of the strike with her two-year-old son, who was due to have surgery this week, when the air raid sirens sounded.

"The nurses told us to go down to the basement. After a while we heard a loud rumble and then the ceiling in the basement collapsed a little," she said at the scene.

"Everyone got very scared, of course. Everyone started screaming and running," she told AFP.

City officials said the attack had also damaged several residential buildings and an office block in Kyiv where AFP reporters saw cars on fire and shredded trees in charred courtyards.

Ukrainian energy operator DTEK also said three electrical substations had been destroyed or damaged in the attack, the latest in series of strikes that have halved the country's energy generation capacity in recent months.

Zelensky said that there were an unknown number of people trapped under the rubble of the Okhmatdyt children's hospital and it was not immediately clear how many had been killed.

An AFP reporter saw one body at the scene, covered with an emergency blanket. Municipal officials said that five people had been pulled from the rubble while at least 10 people had been killed in the barrage that hit Kyiv.

Russian forces have repeatedly targeted the capital with massive barrages since Moscow invaded Ukraine in February 2022, and the last major attack on Kyiv with drones and missiles was last month.

In Zelensky's hometown Kryvyi Rig, which has been repeatedly targed by Russian bombardment, the strikes killed at least 10 and wounded over 41, officials there said.

In Dnipro, a city of around one million people in the same region, one person was killed and six more were wounded, the region's governor said, when a high rise residential building and petrol station were hit.

In the eastern Donetsk region, where Russian forces have taken a string of villages in recent weeks, the regional governor said three people were killed in Pokrovsk - a town that had a pre-war population of around 60,000 people.

There was no immediate comment on the strikes from the Kremlin but it insists its forces do not target civilian infrastructure.

"This shelling targeted civilians, hit infrastructure, and the whole world should see today the consequences of terror, which can only be responded to by force," the head of the presidential administration in Kyiv, Andriy Yermak, wrote on social media, following the attack.

Zelensky and other officials in Kyiv have been urging Ukraine's allies to send more air defence systems, including Patriots, to the war-battered country to help fend off deadly Russian aerial bombardment.

"Russia cannot claim ignorance of where its missiles are flying and must be held fully accountable for all its crimes," Zelensky said in another post on social media.

 - AFP