Russia attacked cities across Ukraine on Monday with a missile barrage that killed more than three dozen people and ripped open a children's hospital in Kyiv, an assault condemned as a ruthless attack on civilians, reports BSS.

Dozens of volunteers including hospital staff and rescue workers dug through debris from the Okhmatdyt paediatric hospital in a desperate search for survivors after the rare day-time bombardment, AFP journalists on the scene saw.

At least 37 people were killed, including three children, with more than 170 wounded, Zelensky said.

The strikes damaged nearly 100 buildings, including multiple schools and a maternity hospital, he added.

The air force said air defence systems downed 30 projectiles.

"It is necessary to shoot down Russian missiles. It is necessary to destroy the Russian combat aircraft on its bases. It is necessary to take strong steps that will not leave any security deficit," Zelensky said ahead of a NATO summit where arming Ukraine's air defences is expected to top the agenda.

Zelensky called for an emergency meeting of the United Nations Security Council over the barrage and urged Ukraine's allies to deliver "a stronger response" to Russia's attack.

Following the strikes, US President Joe Biden on Monday promised "new measures" to boost Ukraine's air defences.

"Together with our allies, we will be announcing new measures to strengthen Ukraine's air defences to help protect their cities and civilians from Russian strikes," Biden said.

UN rights chief Volker Turk condemned the "abominable" Russian strikes, while the body's chief Antonio Guterres said attacking medical facilities was "particularly shocking", according to his spokesman Stephane Dujarric.

The United States denounced "another savage missile attack on civilians", while the European Union slammed Moscow for its "ruthless" actions.

France's foreign ministry called the bombardment of a children's hospital "barbaric" and Canadian Prime Minister Justin Trudeau described the attack as "abhorrent".

Kyiv said the children's hospital had been struck by a Russian cruise missile with components produced in NATO member countries and announced a day of mourning in the capital.

Russia hit back claiming the extensive missile damage in Kyiv was caused by Ukrainian air defence systems.

Moscow said its forces had struck their "intended targets", which it added were only defence industry and military installations.

Medical staff acted quickly to move patients and personnel to the facility's basement after air raid sirens rang out over Kyiv on Monday.

Bd-pratidin English/Tanvir Raihan