Chad's government has accused Sudan of "exporting the genocide" in Darfur across the border.
Some Chadians are fighting back against the attackers
It says there have been "numerous victims" of recent clashes between Arabs and non-Arab groups just across the border from Darfur.
Earlier, a minister said that more than 100 people had been killed in separate clashes in south-eastern Chad.
Eastern Chad and Darfur have a similar ethnic make-up and the two governments have swapped charges of backing rebels.
Chad's government called for UN peacekeepers to be deployed along the border area.
"There is a genocide overflowing from Sudan's region of Darfur," it said about the clashes in the Dar Sila area.
Earlier, National Administration Minister Ahmat Mahamat Bachir said several villages had been burned in last week's violence in Salamat.
He said Arabs had organised attacks on local Kibet villages but that the situation was now under control.
There has been an ongoing dispute between the Arab and the Kibet communities over land issues and water resources.
The BBC's Stephanie Hancock in Chad says there is a general pattern of conflict in the east of the country between Arabs, both from Sudan and Chad, and non-Arab groups.
In April, Chad rebels reached the capital, N'Djamena, before being repulsed.
Sudan denied claims it had backed Chad's rebels, while Chad denied supporting the black African rebels in Darfur.
Some two million people have been displaced in Darfur and at least 200,000 are estimated to have died in the three-and-a-half year conflict.
Sudan's government says it is disarming Arab militias, known as Janjaweed, who have been accused of carrying out genocide on its behalf.
Khartoum also denies claims of genocide.