An investigation in the Democratic Republic of Congo by the BBC has found evidence of a massacre of at least 321 people last December.
Fighters from the rebel group Lord's Resistance Army (LRA) raided several villages in a remote part of north-eastern DR Congo, killing and abducting children.
Human Rights Watch says this is one of the worst massacres carried out by the LRA, whose fighters roam across several countries after spreading from Uganda.
The rebel leaders sow terror in Sudan and Central African Republic, as well as DR Congo.
In the latest attack, the rebels killed villagers and made others carry looted goods. One who was forced to spend days carrying bags of salt says as they marched the rebels killed abductees.
The United Nations had heard rumours that an attack was to be launched around Christmas, and reinforced their troops in the area.
But they were deployed to towns like Dungu and Niangara rather than the remote villages where the killings finally took place.