Ukrainian President Volodymyr Zelenskyy asked global leaders attending the World Economic Forum in Davos to join him in a minute of silence to honour the people killed in a helicopter crash near Kyiv.
A helicopter carrying Ukraine's interior minister crashed into a kindergarten in the suburb of Brovary on Wednesday, killing him and about a dozen other people, including a child on the ground, authorities said.
Interior Minister Denys Monastyrskyy is the most senior official killed since Russia invaded.
Mr Zelenskyy was addressing the Davos summit by video link.
Watch the video in the player above.