Russian strikes battered cities across Ukraine on Friday, killing 26 people including five children, as Kyiv said preparations for a counter-offensive against Moscow's forces were nearly complete.

The deadly new attacks included a strike on a residential block in the historic city of Uman in central Ukraine, where AFP journalists saw rescue workers extracting victims' remains from a destroyed residential building.

The barrage of almost two dozen missiles overnight ended a weeks-long pause following the repeated Russian strikes that had aimed to paralyse Ukraine's energy grid during the winter months.

On Friday evening, workers in Uman, the site of an annual Hasidic pilgrimage, pulled the body of another child from under the rubble. Authorities said Russian cruise missiles killed 23 people -- including four children -- in Uman.

"I want to see my children, they are under the rubble," Dmitry, a 33-year-old local from Lugansk, an eastern city under Russian control, said earlier in the day.

Rescuers were using cranes to search for survivors among the remains of the multi-storey housing block in the central city of 80,000 inhabitants.

"I've seen a lot, but I haven't lost my children before. Now I want to see my children alive or dead," Dmitry said.

Russian missiles also hit the central city of Dnipro, already grief-stricken after a January strike on a tower block that killed more than 40 people.

Authorities said the strikes in Dnipro killed a 31-year-old woman and her two-year-old daughter in their sleep.

The young woman's parents were hospitalised.

"Neighbours say that it was a quiet and kind family," regional authorities said.

Separately, authorities in the southern region of Kherson said on Friday evening that Russian forces shelled the village of Bilozerka, killing a 57-year-old woman and wounding another three.

Ukrainian President Volodymyr Zelensky condemned the latest barrage and vowed a response.

"Only absolute evil can unleash such terror against Ukraine," he said in his evening address.

His advisor Mykhaylo Podolyak tweeted: "If you don't want THIS spread around the world, then give us weapons. Lots of weapons. And add sanctions."

Moscow said it had targeted reserve units of the Ukrainian military and that "all assigned objects were hit."

Moscow-installed officials in eastern Ukraine said that Ukrainian shelling had killed nine people, including an eight-year-old girl in the city of Donetsk.

'We are ready'

There were no reported casualties in Kyiv, which was among the cities targeted Friday.

The capital had not been hit by missiles in more than 50 days, although last week it was attacked by 12 Iranian-made drones, eight of which were shot down without causing any casualties.

Ukraine said overall it had downed 21 of 23 Russian missiles and two attack drones.

The country's air defence system has been bolstered in recent months by the delivery of Western equipment crucial to the country's war effort.

The new strikes came as Ukrainian Defence Minister Oleksiy Reznikov said his country's preparations to push back against entrenched Russian positions were almost complete.

NATO allies and partners have provided Ukraine with 1,550 armoured vehicles and 230 tanks to form units and help it retake territory from Russian forces, NATO chief Jens Stoltenberg said on Thursday.

"Equipment has been promised, prepared and partially delivered. In a global sense, we're ready," Reznikov said.

Kyiv has said throughout the war launched by Russia in February 2022 that it is intent on repelling Moscow's forces from territory they control in eastern and southern Ukraine.

"Preparations are coming to an end," Reznikov added of the planned offensive.

'Only way to survive'

"As soon as there is God's will, the weather and the decision of the commanders -- we will do it."

Most of the fighting has been focused on the eastern Donbas region, particularly the city of Bakhmut, which has been almost completely destroyed.

Several Ukrainian soldiers told AFP that tough clashes in Bakhmut involved not only members of mercenary group Wagner but also Russian special forces.

Not far from Bakhmut, Alex, 34, said the situation was difficult.

"We lack soldiers, we have many wounded, and also dead," he said.

"Sometimes in the trenches, you have to hide behind a corpse," he said. "It's the only way to survive."

Russian Deputy Prime Minister Marat Khusnullin said on Friday he had paid a rare visit to the embattled city and vowed Moscow would rebuild it.

In need of allies to support its drawn-out war effort, Moscow has cultivated its relationship with China.

The leaders of Ukraine and China spoke by telephone this week, with Chinese President Xi Jinping reportedly advocating peace talks.

Xi and Zelensky's discussion on Wednesday was met by Russian accusations that Ukraine was undermining efforts to end the fighting.

Zelensky said Friday he had asked Xi to help bring back Ukrainian children deported by Russia.