Ukrainian's president accused Russia of carrying out genocide after officials said Russian aircraft bombed a children's hospital on Wednesday, burying patients in rubble despite a ceasefire deal for people to flee the besieged city of Mariupol.
The attack, which authorities said injured women in labour and left children in the wreckage, is the latest grim incident of the 14-day invasion, the biggest assault on a European state since 1945.
The Mariupol city council said the hospital had been hit several times in what the White House called a "barbaric use of military force to go after innocent civilians".
The destruction took place despite a Russian pledge to halt firing so at least some trapped civilians could escape the city, where hundreds of thousands have been sheltering without water or power for more than a week.
"What kind of country is this, the Russian Federation, which is afraid of hospitals, is afraid of maternity hospitals, and destroys them?" Ukrainian President Volodymyr Zelenskyy said in a televised address late on Wednesday.
Zelenskyy repeated his call for the West to tighten sanctions on Russia "so that they sit down at the negotiating table and end this brutal war". The bombing of the children's hospital, he said, was "proof that a genocide of Ukrainians is taking place".
Kremlin spokesman Dmitry Peskov, said: "Russian forces do not fire on civilian targets." Russia calls its incursion a "special operation" to disarm its neighbour and dislodge leaders it calls "neo-Nazis."
Ukraine's foreign ministry posted video footage of what it said was the hospital showing holes where windows should have been in a three-storey building. Huge piles of smouldering rubble littered the scene.
The U.N. Human Rights body said it was verifying the number of casualties at Mariupol.
"The incident adds to our deep concerns about indiscriminate use of weapons in populated areas and civilians trapped in active hostilities in numerous areas," said spokesperson Liz Throssell.
The Donetsk region's governor said 17 people were wounded in the attack.
Ukraine accused Russia of breaking the ceasefire around the southern port, which aid workers and officials say is running out of food and water after days of Russian bombardment.
"Indiscriminate shelling continues," Foreign Minister Dmytro Kuleba wrote on Twitter.
Satellite image company Maxar said images from earlier in the day showed extensive damage to homes, apartment buildings, grocery stores and shopping centres in the port city.
Russia blamed Ukraine for the failure of the evacuation.
