Ukrainian President Volodymyr Zelenskyy on Tuesday said Kyiv would respond after the country was hit by a fresh round of Russian strikes overnight.

Zelenskyy said four people died in the fresh strikes.

The Ukrainian leader posted on X: " Rescue operations are ongoing at the sites of strikes and falling debris in the regions of Ukraine that were attacked by Russia last night. All services are on the ground, and the rubble is being cleared.

"Unfortunately, despite the effective work of our air defense, 4 people were killed and 16 were injured. My condolences to the families and loved ones of the victims," he said.

He said: "In total, the enemy used over 90 aerial targets against civilians and infrastructure: 81 Shahed drones, as well as cruise, ballistic, and air-launched ballistics missiles."

Vowing his nation would respond, he said, "We will undoubtedly respond to Russia for this and all other attacks. Crimes against humanity cannot go unpunished."

Joe Biden condemns attack

US President Joe Biden has condemned the latest round of Russian strikes which he said will plunge people of the nation into darkness.

" Earlier today, Russia launched missiles and drones against Ukrainian cities and energy infrastructure," he said.

" I condemn – in the strongest possible terms – Russia’s continued war against Ukraine and its efforts to plunge the Ukrainian people into darkness," Biden said.

The UN Humanitarian Coordinator for Ukraine has condemned deadly Russian missile and drone strikes that began overnight and reportedly targeted 15 regions of the country.

“Like millions of people in Ukraine I spent hours in a shelter this morning because of the ongoing wave of attacks on Ukraine by the Russian Armed Forces,” Matthias Schmale said in a statement issued on Monday.

He added that civilians were reportedly killed and injured, while civilian infrastructure sustained heavy damage.

--Separately, the UN Children’s Fund (UNICEF) in Ukraine wrote on the social media platform X that boys and girls “woke up today to sounds of air alarms and explosions”.

The office also shared photos of children and families sheltering at metro stations in the capital, Kyiv.

The Representative for the UN reproductive and sexual health agency, UNFPA, in Ukraine also deplored the aerial assault in a post on X.

Massimo Diana said the attacks “tragically claimed lives” in the city of Lutsk and in the Zhytomyr region.

“We condemn these deadly assaults on critical infrastructure and call for urgent action to protect civilians,” he said.