"The two villages were partially burned down," the minister said in his statement, adding that nine of the attackers were killed and four taken prisoner.

The attacks took place near the border with Sudan where the United Nations refugee agency runs a camp for people displaced by the violence in Darfur.

Eastern Chad has suffered a rise in violence in recent months, including Janjawid raids and inter-communal clashes between Arabs and non-Arabs which have killed hundreds, as well as attacks by Chadian fighters opposed to Idriss Deby, the president of Chad.