“The great holiday today gives us great hope and unwavering faith that light will overcome darkness, good will overcome evil, life will overcome death, and therefore Ukraine will surely win!” Zelensky said on Sunday from the ancient St Sophia Cathedral.

Hours earlier, the president said he was preparing for “important talks with American partners”. The US State Department declined to comment on the highly sensitive trip by two of President Joe Biden’s top cabinet members.

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Russia strikes Mariupol steel plant that has become Ukraine’s stronghold in strategic city

Russia strikes Mariupol steel plant that has become Ukraine’s stronghold in strategic city

Their visit comes as Russian forces show no sign of easing their attacks after a missile strike on the southern city of Odesa that killed eight people, including an infant.

“Among those killed was a three-month-old baby girl. How did she threaten Russia? It seems that killing children is just a new national idea of the Russian Federation,” Zelensky said.

He also accused Russia of being a terrorist state and of acting like Nazis in the shattered port city of Mariupol, which has been devastated by weeks of intense bombardment.

The latest of many attempts to evacuate civilians from Mariupol failed Saturday, and an embattled unit of Ukrainian fighters holed up in tunnels under the sprawling Azovstal steel mill there appeared in increasingly desperate straits.

About 200 residents gathered at a designated evacuation point in Mariupol on Saturday, but were “dispersed” by Russian forces, city official Petro Andryushchenko said on Telegram, adding: “The evacuation was thwarted.”

He claimed others had been told to board buses headed to places controlled by Russia.

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In a message posted on social media on Sunday, Sviatoslav Palamar - deputy commander of the far-right Azov Regiment - said Russian forces continued to rain down fire on Azovstal as its troops attempted to breach the plant’s defences.

“The enemy continues air strikes, artillery from the sea ... enemy tanks continue to strike and infantry is trying to storm,” said Palamar.

Mariupol, which the Kremlin claims to have “liberated”, is pivotal to Russia’s war plans to forge a land bridge to Russian-occupied Crimea - and possibly beyond, as far as Moldova.

The United Nations Ukraine crisis coordinator, Amin Awad, on Sunday called for an “immediate stop” to fighting in Mariupol to allow the evacuation of trapped civilians in the battered city “today”.

“The lives of tens of thousands, including women, children and older people, are at stake in Mariupol,” Awad said in a statement. “We need a pause in fighting right now to save lives. The longer we wait the more lives will be at risk. They must be allowed to safely evacuate now, today. Tomorrow could be too late.”

And even as fighting raged across large swaths of the country, Ukrainians took time to observe a solemn Easter in the largely Orthodox country.

St. Volodymyr’s Cathedral in Kyiv was ringed by hundreds of worshipers with baskets to be blessed. Inside, a woman clutched the arm of a soldier, turning briefly to kiss his elbow. Other soldiers prayed, holding handful of candles, then crossed themselves. An older woman slowly made her way through the crowd and stands of flickering candles. One young woman held daffodils.

Outside the cathedral, a soldier who gave only his first name, Mykhailo, used his helmet as an Easter basket. He said he didn’t have another.

“I hope I’ll only have to use the helmet for this,” he said.

Under the rain at a military position in the eastern town of Lyman, on the frontline, soldiers traded the usual patriotic salutation of “Glory to Ukraine!” for the ritual “Christ has risen!”.

In the town’s small Orthodox church, around 50 civilians had braved possible mortar fire to gather to pray from dawn.

Ukrainian and Russian artillery fire could be heard throughout the singing of the psalms.

“If we make the wrong choices then darkness will ruin us, as darkness is destroying us during this war,” the priest said in his sermon.

On another part of the frontline, in the eastern city of Severodonetsk, Ukrainian troops had hidden their small stock of supplies under a bridge after they were hit by Russian mortar rounds in the night.

Along with water and Coke bottles, Kalashnikovs and cereal bars, three large Easter breads covered in icing and sprinkled with multicoloured sugar beads awaited them, after a delivery from their commander.

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The modest Easter celebrations came just a day after missile struck a residential building in the Black Sea port of Odesa, killing eight people and wounding at least 18, according to Zelensky, who said five missiles hit the historic city.

“We will identify all those responsible for this strike; those responsible for Russia’s missile terror,” he said.

Russia’s defence ministry said it had targeted a major depot stocking foreign weapons near Odesa, attacks that upended the relative calm the city has enjoyed since the beginning of the war.

The ministry also charged that Ukrainian special services in Odessa were preparing a “provocation with the use of toxic chemical substances” that could then be blamed on Russia.

Meanwhile, European Commission President Ursula von der Leyen was set to press India over its neutral stance on the Ukraine war after arriving in the country on Sunday for trade, security and climate talks.

New Delhi has long walked a tightrope in its relations with the West and Moscow – which supplies most of India’s arms – and Russia’s invasion of its neighbour has highlighted the difficulty of the balancing act.

Prime Minister Narendra Modi’s government has not openly condemned the Kremlin or backed a UN Security Council vote that deplored Moscow’s “aggression”.

Von der Leyen will meet Modi on Monday as the latest in a stream of recent diplomatic visitors seeking to lure India away from Russia with pledges of security, defence and energy cooperation.

Additional reporting by AP