At least 23 people have been killed in a new bout of ethnic violence in eastern Chad, bringing the death toll since Thursday to more than 35, local officials said.
Fighting erupted on Sunday in three villages in Sila province and continued on Monday, they said.
Interim regional governor Oumar Sanda Makache III said 23 people had died in Sila, after the villages were torched Sunday and Monday.
"The situation is now under control," he added, saying security forces had been deployed to the area.
Twelve people were killed on Thursday in the neighbouring province of Ouaddai when a village was attacked by armed men, provincial public prosecutor Hassan Djamouss Hachimi said.
"We arrested 30 people," he said.
Eastern Chad is grappling with tit-for-tat violence between native Ouaddian farmers and Arab herders, an issue raised during a visit to the region in February by President Idriss Deby.
Idriss had on that occasion acknowledged "serious" unrest, warning "the time is over for vendettas" between the rival groups and that it was for the judicial system to dispense justice.
Hachimi said nine Ouaddai farmers and three herders were killed.
The minister for public security, Mahamat Abali Salah, had Saturday been in the region, where several weapons were found, national radio reported.
The ministry said he was on his way to Sila, where last November a dozen people were killed in two deadly attacks near Abeche, Ouaddai's regional capital.
Over all of last year Ouaddai hospitals treated more than 100 people for bullet wounds.
Mahamat Saleh Yacoub, a historian, told AFP last month that drought and population growth region had inflamed tensions between the two groups.
Most of the herders' animals belong to the president's Zaghawa ethnic group, and the farmers say they often escape censure when unrest breaks out between them.
Similar conflicts between herders and farmers erupt in other African states, notably Nigeria.