A U.N. human rights expert has condemned attacks on Sudanese protesters that left six killed, including an army officer, earlier this week, calling on the ruling military council to ensure the protection of peaceful demonstrators.

Aristide Nononsi, the U.N. independent expert on the human rights situation in Sudan, was quoted in a press release on Friday urging the transitional military council to conduct an impartial investigation into the killings of all protesters since the outbreak of the uprising in December 2018.

The military removed President Omar al-Bashir from power in April, and has been locked in political negotiations with a coalition of opposition groups since. Protesters have continued staging regular rallies and sit-ins demanding the generals hand power over to civilians.