More than 100 people were killed in clashes between Arab and non-Arab tribes in southeastern Chad last week, the government said on Tuesday.
"There was a problem between the Arabs and the Kibets (a non-Arab tribe) one week ago (on October 31)," National Administration Minister Ahmat Mahamat Bachir said, without elaborating on the nature of the problem.
He said the initial clashes had left three dead in each community.
"The Arabs in neighbouring districts then organised attacks on the Kibet villages," Bachir told by telephone from Am Timan, the main town in the Salamat region, where the clashes took place.
He said several villages had been burned in the unrest, which left "more than 100 dead", a number of wounded and forced others to flee their homes.
A local human rights activist, who asked to remain anonymous, said at least 140 people had been killed, 30 wounded and 400 huts burnt to the ground.
Bachir said calm had been restored to the region on November 4.
The minister has been in leading a delegation in Salamat for the past three days "to assess the damage and conduct enquiries".
The region of Salamat borders the Central African Republic and is near the war-torn Sudanese region of Darfur, where fighting between government-backed Arab militias and non-Arab locals have killed at least 200,000 people since early 2003.
In October, Salamat was the scene of clashes between the army and rebels from the Union for the Forces of Democracy and Development (UFDD), a newly formed coalition opposed to the regime of President Idriss Deby Itno.
The rebels briefly occupied Am Timan and the eastern town of Goz Beida on October 23. The incident led N'Djamena to accuse neighbouring Sudan of supporting the rebels, an allegation both Khartoum and the UFDD have denied.
The Chadian authorites did not on Tuesday establish any link between the presence of rebels in the east and the clashes between Arabs and Kibets last week.
Communal violence, often sparked by long-standing rivalities or land disputes, has become increasingly common in Chad.