Dozens of Ukrainians were killed on Tuesday in a Russian missile attack on the central Ukrainian city of Poltava, one of the deadliest strikes of the two-and-a-half-year war.
President Volodymyr Zelensky vowed to hold "Russian scum" accountable for the attack on a military education facility and nearby hospital, which killed at least 41 and wounded another 180.
The strike triggered anger on Ukrainian social media after unconfirmed reports said it had targeted an outdoor military ceremony, with many blaming reckless behaviour from officials who allowed the event to take place despite the threat of Russian attacks.
Zelensky said he had ordered a "full and prompt investigation into all the circumstances of what happened".
"More than 180 people were injured. Unfortunately, there are many dead. As of now, 41 people have been reported dead," Zelensky said in a post on social media.
Two Russian ballistic missiles hit the hospital and an educational institution, partially destroying one of the buildings, Zelensky said.
"The time interval between the alarm and the arrival of the deadly missiles was so short that it caught people in the middle of evacuating to the bomb shelter," the defence ministry said.
The strike took place in the morning in Poltava, a city with a pre-war population of around 300,000 people, located 300 kilometres (189 miles) east of Kyiv.
The Poltava military communications institute, founded in the 1960s when Ukraine was part of the USSR, specialises in training telecommunications specialists.
"One of the institute's buildings was partially destroyed, and many people were trapped under the rubble," the defence ministry said.
An AFP journalist on the scene saw several ambulances heading towards the affected site shortly after the attack on the military institute.
Rescuers were still at work after having managed to save 25 people, including 11 trapped under the rubble, the defence ministry said.
Official channels and local media shared messages urging locals to donate blood to help treat the wounded.
At the same time criticism of Ukrainian officials swirled online.
"Poltava... How can such a large number of people gather at such a facility?" said blogger Sergey Naumovich.
There had been some reports from Russian military bloggers that the strike targeted an outdoor ceremony.
Poltava Governor Philip Pronin said his administration could not provide more details of the circumstances of the strike "for security reasons".
"The enemy is using any means to bring Ukraine more pain and disorientate Ukrainians. Please trust only reliable sources," he said.
Ukrainian MP Maria Bezugla, who regularly criticises the country's military leadership, accused high-ranking officials of endangering soldiers by allowing such events.
"These tragedies keep repeating themselves. When will it stop?" she posted on Telegram.
Zelensky said he ordered a "full and prompt investigation" into the strike and vowed to keep Russia accountable.
The attack follows another recent scandal for Ukraine's army command after a US-made F-16 fighter jet crashed in combat last week, killing the pilot.
The crash of the F-16 was a high-profile setback for Kyiv, which had lobbied the West to send the advanced fighter jet for months, and triggered the dismissal of the country's air force chief Mykola Oleshchuk.
