President Volodymyr Zelenskyy shook up his wartime government, drawing thousands into the streets Thursday across Ukraine to protest the ouster of his youthful defense minister, Mykhailo Fedorov. Fedorov is seen as an innovator of the country’s successful drone technology but who clashed with the traditional military establishment.

As Russian attacks grind on, Volodymyr Zelensky has sacked his hugely popular defence minister Mykhailo Fedorov, triggering rare wartime protests and a crisis of confidence in Kyiv.

Fedorov, 35, was appointed only in January but has been credited with energising the ministry, heading a drive against corruption and using data to analyse and try to improve performance on the front ...