President Volodymyr Zelensky told Ukrainians on Thursday they should be proud of having survived 50 days under Russian attack when the Russians “gave us a maximum of five”.

In his late-night video address to the nation, Mr Zelenskyy called it “an achievement of millions of Ukrainians, of everyone who on February 24 made the most important decision of their life – to fight”.

The president gave an extensive and almost poetic listing of the many ways in which Ukrainians have helped to fend off the Russian troops, including “those who showed that Russian warships can sail away, even if it’s to the bottom” of the sea.

It was his only reference to the Russian missile cruiser Moskva, which sank while being towed to port.

Russia invaded on February 24 and has lost potentially thousands of fighters. The conflict has killed untold numbers of Ukrainian civilians and forced millions more to flee.

Mr Zelensky said he remembered the first day of the invasion when many world leaders, unsure whether Ukraine could survive, advised him to leave the country.

He added: “But they didn’t know how brave Ukrainians are, how much we value freedom and the possibility to live the way we want.”

It came as the head of the UN World Food Programme (WFP) said people are being “starved to death” in the besieged Ukrainian city of Mariupol and he predicted the country’s humanitarian crisis is likely to worsen as Russia intensifies its assault in the coming weeks.

A serviceman stands at a building damaged during fighting in Mariupol
Mariupol has seen some of the worst suffering since the invasion began (Alexei Alexandrov/AP)

WFP executive director David Beasley also warned in an interview Thursday with The Associated Press in Kyiv that Russia’s invasion of grain-exporting Ukraine risks destabilising nations far from its shores and could trigger waves of migrants seeking better lives elsewhere.

His fears were shared by the US ambassador to the United Nations, who accused Russia of making the precarious food situation in Yemen and elsewhere worse by invading Ukraine, calling it “just another grim example of the ripple effect Russia’s unprovoked, unjust, unconscionable war is having on the world’s most vulnerable”.

Linda Thomas-Greenfield told a UN Security Council meeting on war-torn Yemen on Thursday the WFP had identified the Arab world’s poorest nation as one of the countries most affected by wheat price increases and lack of imports from Ukraine.

Russia’s deputy UN ambassador Dmitry Polyansky replied: “The main factor for instability and the source of the problem today is not the Russian special military operation in Ukraine, but sanctions measures imposed on our country seeking to cut off any supplies from Russia and the supply chain, apart from those supplies that those countries in the West need, in other words energy.”

The sharp exchange took place a day after a UN taskforce warned the war threatens to devastate the economies of many developing countries that are now facing even higher food and energy costs and increasingly difficult financial conditions.

Meanwhile, Russia’s Defence Ministry has promised to ramp up “the scale of missile attacks” on Kyiv in response to what it called Ukraine’s “diversions on the Russian territory.”

Russian invasion of Ukraine
(PA Graphics)

The statement comes a day after Russian authorities accused Ukrainian forces of launching air strikes on residential buildings in one of the country’s regions on the border with Ukraine, in which seven people sustained injuries.

According to Russian officials, some 100 residential buildings were damaged in Thursday’s attack on the village of Klimovo in the Bryansk region.

The Defence Ministry said that the Russian forces in Ukraine’s Chernihiv region shot down a Ukrainian helicopter that was allegedly involved in the attack on the Bryansk region.

Authorities in another border region, Belgorod, also reported Ukrainian shelling on Thursday.