KRAMATORSK, Ukraine - Ukraine is preparing for "important battles" against Moscow's forces in the east of the country, officials in Kyiv said, as Pope Francis on Sunday called for an Easter truce to end the war.

Evacuations continued from Kramatorsk, in eastern Ukraine, where a missile strike on Friday killed 52 people at a railway station, while an airport in the central city of Dnipro was completely destroyed in fresh shelling Sunday.

President Volodymyr Zelensky again condemned atrocities against civilians, and after speaking with German Chancellor Olaf Scholz said they agreed "that all perpetrators of war crimes must be identified and punished".

Ukraine's prosecutor general Iryna Venediktova said the country was examining the alleged culpability of 500 leading Russian officials for thousands of war crimes, including President Vladimir Putin.

Pope Francis meanwhile called for an Easter ceasefire in Ukraine to pave the way for peace through "real negotiation".

"Let the Easter truce begin. But not to provide more weapons and pick up the combat again -- no! -- a truce that will lead to peace, through real negotiation," he told a public mass at Saint Peter's Square.

The pontiff denounced a war where "defenseless civilians" suffered "heinous massacres and atrocious cruelty".

But Russia's Orthodox Patriarch Kirill, a key Putin ally, issued his own appeal against Russia's "enemies".

"In this difficult period for our fatherland, may the Lord help each of us to unite, including around power," he said.

"This is how true solidarity will emerge in our people, as well as an ability to push back external and internal enemies, and to build a life with more good, truth and love."

'READY TO FIGHT'

The appeals came after Zelensky said Kyiv was readying for a Russian onslaught.

"Sadly, in parallel we see the preparations for important battles, some people say decisive ones, in the east," he said Saturday at a press conference with visiting Austrian Chancellor Karl Nehammer.

"We are ready to fight and to look in parallel to end this war through diplomacy."

The UN on Sunday said 4,232 civilian casualties had been recorded in Ukraine to date, with 1,793 killed and 2,439 injured.

Ukraine said Kremlin propaganda had laid the groundwork for the bloody campaign, accusing Russian media of long sowing hatred towards Ukrainians.

Foreign Minister Dmytro Kuleba cited civilian killings in the town of Bucha outside of Kyiv after bodies were discovered as the Russian army retreated from the area.

"Bucha did not happen in one day," he said on Twitter Sunday.

"For many years, Russian political elites and propaganda have been inciting hatred, dehumanizing Ukrainians, nurturing Russian superiority and laying ground for these atrocities."

'MY SON, MY SON'

The comments came on the heels of a surprise visit to Kyiv on Saturday by British Prime Minister Boris Johnson, the latest Western leader to visit the capital in a show of support.

Hailing the country's response to the Russian invasion, Johnson offered Ukraine armored vehicles and anti-ship missiles, crucial to halting the Russian naval siege of Black Sea ports, to help ensure that the country will "never be invaded again".

A video released by Zelensky's office showed him and the British prime minister walking through largely empty city streets to Kyiv's historic Maidan Square, as snipers kept watch.

Johnson said the discovery of scores of civilian corpses in Ukrainian towns had "permanently polluted" Putin's reputation.

At least two bodies were found inside a manhole at a petrol station on a motorway outside Kyiv on Sunday, an AFP reporter saw.

The bodies appeared to be wearing a mix of civilian and military clothing.

A distraught woman appeared at the manhole and peered inside, before breaking down and clawing the earth.

She wailed "my son, my son".

In further Russian strikes, the airport in the central of Dnipro was completely destroyed in fresh shelling, a local official said Sunday.

"The airport itself and the infrastructure around it has been destroyed. Rockets keep flying and flying," the head of the city's military administration, Valentin Reznichenko, said on Telegram.

Moscow has shifted its focus to eastern and southern Ukraine after stiff resistance thwarted plans to swiftly capture Kyiv.

With thousands killed in the fighting and more than 11 million fleeing their homes, the Ukrainian president called on the West to follow Britain's example on military aid.

"We need even more sanctions" against Russia, Zelensky said in a video address Saturday.

"We need more weapons."

'NEW NORMAL'

As Russian forces regroup in the east and south of Ukraine, local officials are urging residents to flee before it is too late.

At least two people were killed in the bombardment of the northeastern city of Kharkiv and its surroundings, governor Oleg Sinegubov said on Facebook on Sunday, reporting 66 strikes in 24 hours.

"The Russian army continues to wage war on civilians due to a lack of victories at the front," he said.

The mayor of eastern Lysychansk, Oleksandr Zaika, asked residents to evacuate as soon as possible due to constant shelling by the Russian army.

Speaking Saturday from Warsaw, European Commission President Ursula von der Leyen said a global pledging event for the more than 4.5 million refugees who have fled the country had raised 10.1 billion euros ($11 billion).

In another sign of Western solidarity, NATO Secretary General Jens Stoltenberg said the military alliance was drawing up plans for a permanent military force on its border to prevent further Russian aggression.

"What we see now is a new reality, a new normal for European security," he said in an interview with Britain's Daily Telegraph.

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