Defence minister Mykhailo Fedorov was sacked last month. The move from an architect of Ukraine’s drone program is a remarkably direct challenge to President Volodymyr Zelensky’s authority and may test Ukrainian unity. Key points and original sources are listed below.

• Defence minister Mykhailo Fedorov was sacked last month.S1

• The move from an architect of Ukraine’s drone program is a remarkably direct challenge to President Volodymyr Zelensky’s authority and may test Ukrainian unity.S2