Russia was on Monday accused of a “cowardly and depraved attack” after a missile strike hit a major children’s hospital in Kyiv.
Barbara Woodward, the UK's permanent representative to the United Nations (UN), said the attack on the Okhmatdyt children’s hospital would be discussed at an emergency meeting of the UN Security Council on Tuesday.
Kyiv mayor Vitali Klitschko said two adults had been confirmed dead in the attack.
He added that rescuers feared that the death toll could rise as more people remain trapped under the rubble.
At least 33 people were killed in Russian strikes across Ukraine on Monday, according to Ukrainian officials.
In the capital, Kyiv, at least ten people were killed in a rare daytime attack.
Ms Woodward wrote on X: “The children of Okhmatdyt Children’s Hospital gave me this last year. It hangs in my office.
“We will call out Russia's cowardly and depraved attack on the hospital last night in the Security Council.
“As David Lammy said: we will hold those responsible for this war to account.”
UN secretary-general António Guterres “strongly condemned” the attack on the hospital, his spokesperson Stéphane Dujarric said.
Ukrainian President Volodymyr Zelensky said Russia had targeted five cities with more than 40 missiles of different types.
Speaking in Poland, he called the attack on the children’s hospital a “direct strike” and insisted it was deliberate.
He vowed to “respond” to the strikes but called on Ukraine’s allies to “take responsibility”.
Elsewhere, at least 10 people were killed in the central Ukrainian city of Kryvyi Rih, with three killed in the eastern town of Pokrovsk and one in Dnipro.
The attacks included Kinzhal hypersonic missiles, one of the most advanced Russian weapons, the Ukrainian air force said.
The Kinzhal flies at 10 times the speed of sound, making it hard to intercept. City buildings shook from the blasts.
At the children's hospital, a two-story building was partly destroyed. On the hospital's main 10-story building, windows and doors were blown out and walls were blackened. Blood spattered the floor in one room.
Medical personnel and local people helped shift the rubble as they searched for children and medical workers who could be trapped underneath. Volunteers formed a line, passing stones and debris to each other. Smoke still rose from the building, and volunteers and emergency crews worked in protective masks.
The attack forced the hospital to shut down and evacuate. Some mothers carried their children away on their backs. Others waited in the courtyard with their children as calls to doctors' phones rang unanswered.
An entire section of a residential multistory building in one district of Kyiv was destroyed, officials said. Three electricity substations were damaged or completely destroyed in two districts of Kyiv, energy company DTEK said.
The attack came on the eve of a three-day Nato summit in Washington, which will look at how to reassure Ukraine of the alliance’s unwavering support and offer Ukrainians hope that their country can come through Europe’s biggest conflict since the Second World War.
Sir Keir Starmer is set to attend the summit, his first international event since becoming prime minister.
He spoke with Mr Zelensky shortly after the election results came in and said that the change to a Labour government “makes no difference to the support you will see” from the UK in response to the Russian invasion.
John Healey, Labour’s new defence secretary, this weekend announced a fresh package of military aid when he made an impromptu visit to Ukraine’s southern port of Odesa.
Mr Zelensky, who is also due to travel to the US for this week’s Nato summit, said Russia had “massively attacked” Ukraine.
“Different cities: Kyiv, Dnipro, Kryvyi Rih, Sloviansk, Kramatorsk. More than 40 missiles of various types. Residential buildings, infrastructure and a children’s hospital were damaged,” he said.
Plumes of smoke could be seen across the capital Kyiv, while video posted on social media showed the destruction inside and outside of the Okhmadyt children’s hospital
It was not immediately clear if anyone inside was injured.
But Mr Zelensky said in a social media post that people were trapped under the rubble of the hospital.
Elsewhere, Oleksandr Vilkul, head of the military administration in Kryvy Rih, posted on the Telegram messaging app that at least 10 people were killed and 31 wounded following the attack on the city. Of those, he said 10 were seriously injured.
Kryvy Rih is Mr Zelensky’s home town and has been repeatedly attacked by Russia since it launched its full-scale invasion of Ukraine in February 2022.
The Russian bombardment comes as Indian Prime Minister Narendra Modi arrived in Moscow for a two-day state visit to Russia where he is due to hold talks with President Vladimir Putin at the Kremlin.
