At least 16 people have been killed in a row over a disputed charge on the sale of caterpillars in the Democratic Republic of Congo.
The larvae were being sold for food in south-eastern Katanga province.
Days of violence began when a group of Batwa, also known as pygmies, accused the Luba ethnic group of imposing an illegal levy on the sale of caterpillars and beating up vendors.
The two groups have clashed several times in the last few years.
The Batwa killed several members of the Luba ethnic group near the region of Kabalo in Katanga. The Luba then launched a revenge attack, killing at least 13 pygmies.
Tensions between the hunter-gatherer pygmies and the Luba, a Bantu ethnic group, have caused hundreds of deaths over the past three years.
Analysis - Poly Muzalia, BBC Africa, Kinshasa
Caterpillars are a delicacy in western DR Congo, in the area around the capital Kinshasa, hundreds of miles from Katanga where the deadly clashes occurred.
They are harvested from trees, smoked and often eaten with sauce.
However they are an unexpected cause of conflict in DR Congo, particularly in Katanga.
That province is not known for its love of eating caterpillars and people have certainly never killed for them before.
But there is a running feud in the area between pygmies and other ethnic groups.
Pygmies are native to the region but they feel they are marginalised, with unequal access to resources and education.
So when they felt that one of their main sources of income was being subject to an unfair tax, the result was violence.