Ukraine's Interior Minister and his deputy were among 18 people killed on Wednesday after a helicopter crashed beside a kindergarten in a suburb of the capital Kyiv.
Authorities have not specified the cause of the crash, whose death toll included three children.
Kyiv's regional military administration said the tragedy had left 29 people injured. Reports say 22 people are in hospital including 10 children.
The 42-year-old minister, Denys Monastyrsky, was with eight others in the helicopter – including his first deputy minister and the state secretary – when it came down in the eastern suburb of Brovary.
War 'hot spot'
Ukraine's presidential office said Monastyrsky had been en route to a war "hot spot" when the helicopter, which belonged to Ukraine's state emergency service, went down.
It is understood to have been flying low, and there is no indication that enemy fire was to blame.
A prominent member of President Volodymyr Zelensky's cabinet, Monastyrsky played a key role in updating the public on casualties caused by Russian missile strikes.
He was a trained lawyer with two children and had served as Ukraine's Interior Minister from July, 2021.
In a statement on social media, Zelensky called the crash a “terrible tragedy”, adding the pain was "unspeakable".
Ukrainian Prime Minister Denys Chmygal called it "a great loss for the government and the whole state".
"My sincere condolences to the families of all the victims. I instructed (officials) to immediately create a special group for a detailed investigation of all the circumstances of the tragedy," Chmygal said on Telegram.
In a tweet, European Council head Charles Michel described Monastyrskyi as a "great friend of the EU".
The deadly incident came as Ukraine edged closer to winning approval for German-made modern battle tanks to confront Russia's invading forces.
