KYIV, Ukraine (AP) — Russian attacks on Ukraine overnight killed at least four civilians and wounded 20 other people, President Volodymyr Zelenskyy said, as he faces a political crisis after firing his popular defense minister.Zelenskyy’s major reshuffle of his government on Thursday, which included the appointment of a new prime minister, unsettled the country’s military leadership and trigged a public outcry. It was an unwelcome difficulty after Ukraine has gained traction in its fight against Russia’s more than 4-year-old invasion.The surprise departure from the defense ministry of Mykhailo Fedorov, a youthful and popular member of the government, saw thousands of people demonstrate against his dismissal in cities across Ukraine on Thursday. Further street protests were expected on Friday.Fedorov, 35, who was in the post for just six months, is widely seen as the driving force behind Ukraine’s swift and successful technological innovation and other measures, such as fighting military corruption, that have brought fresh hope in the war for Ukrainians.Relations between Fedorov and Gen. Oleksandr Syrskyi, the commander of Ukraine’s armed forces who started his military career in the former Soviet Union, had broken down, according to Zelenskyy, and made Fedorov’s position untenable.