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.