Investigators say peacekeepers left their posts in attack on UN-protected site in city of Malakal that killed 40 people.
MORE FROM AUTHOR
Swearing-in ceremony follows Machar’s return to the capital after UN peace deal aimed at ending two-year war.
Formation of unity government expected if rebel leader arrives in capital Juba in first step towards ending civil war.
Disagreement over weapons is preventing rebel leader from returning to Juba to form unity government, officials say.
Effort to form unity government and end civil war thrown into limbo after return of Riek Machar is repeatedly delayed.
Instead of being places of care and refuge, medical facilities have become the sites of massacres and looting.