A camel herder puts down his animals for the night, in a village in the Mao region. AFP
Tensions between semi-nomadic Arab herders and sedentary indigenous farmers is a traditional problem in central and southern Chad.
They often arise when farmers accuse herders of allowing their animals to eat or trample on their crops.
The latest deadly clash began on Tuesday as an altercation between a farmer and a herder in Marabe, a small village some 700 kilometres (435 miles) south of the capital N'Djamena.
The trouble spread to two neighbouring villages on Wednesday, said Ali Ahmat Akhabache, governor of the Moyen-Chari province bordering the Central African Republic.
"Ten people died and 20 were injured," he told AFP by phone, adding that police had managed to restore calm "and the situation has been fully under control" since Wednesday.
Last month, 22 people were killed in clashes between farmers and herdsmen in an area 500 km south of N'Djamena.
Violence between the two communities has become common in central and southern Chad, where many of the inhabitants are armed.
Thanks to southern Chad's relatively mild climate for the Sahel, its vegetation is lush, and for centuries it has drawn in migratory herders from arid areas, many of them Arabs, for seasonal grazing.
The nomads generally come from the arid Sahelian zones of northern Chad and increasingly want to settle in more fertile land where they can raise their camels and sheep.