Interior minister Denys Monastyrskyi, his deputy Yevhen Yenin, and state secretary of the Ministry of Internal Affairs Yurii Lubkovych were among those killed, according to Ihor Klymenko, chief of Ukraine’s National Police.
Mr Monastyrskyi is the most senior Ukrainian official to have died since the start of the war with Russia almost 11 months ago.
Nine of those killed were on board the emergency services helicopter that crashed in Brovary, an eastern suburb of the capital Kyiv, Mr Klymenko said.
Ukraine’s State Emergency Service said at least 14 people were killed, including the nine aboard the helicopter, and a child on the ground. It said 25 people were injured, including 11 children. Early official reports gave differing numbers of casualties.
Earlier, officials and media reports said the helicopter crashed near a nursery school.
There was no immediate word on whether the crash was an accident or a result of the war with Russia. No fighting has been reported recently in the Kyiv area.
Foreign Secretary James Cleverly said Mr Monastyrsky was “a true friend of the UK”.
He described the death as “tragic” and pledged: “We are ready to support Ukraine in whatever way we can.”
Home secretary Suella Braverman said his death was “truly heart-breaking”, adding: “Interior minister Denys Monastyrsky was a leading light in supporting the Ukrainian people during Putin’s illegal invasion and when we spoke in October I was struck by his determination, optimism and patriotism.
“My thoughts go out to all those who have died in this horrible tragedy and their families. The UK will always stand with our Ukrainian friends.”
Ukraine first lady Olena Zelenska was seen dabbing her eyes and pinching her nose in emotion minutes before attending the World Economic Forum session in Davos, Switzerland.
“Another very sad day today – new losses,” she said.
Ukraine president Volodymyr Zelensky said the crash had a broad connection to the war as he addressed the World Economic Forum in Davos by video link.
“This is not an accident because it has been due to war and the war has many dimensions, not just on the battlefields,” he said after asking the Davos audience to stand and join him in a minute of silence to honour those killed. “There are no accidents at wartime. These are all war results.”
Forum president Borge Brende requested a few moments of silence after opening the session to honour the Ukrainian officials killed in the crash.
The crash came just four days after a Russian missile strike on an apartment building in south-eastern Ukraine killed 45 civilians, including six children – the deadliest attack on civilians since the spring.
“Haven’t had time to recover from one tragedy, there is already another one,” said the deputy head of the Ukrainian presidential office, Kyrylo Tymoshenko.