Chad's senior army commander has been killed in fighting with rebels on its border with Sudan, army officials say.
Many soldiers have deserted to rebel ranks
Gen Abakar Itno - the nephew of Chad's President Idriss Deby - died of injuries in clashes in the Moudeina area, south of the border town of Adre.
Chad alleges Rally for Democracy and Liberty rebels receive support from the Janjaweed militia operating in the neighbouring Sudanese region of Darfur.
Aid officials say the fighting involved about 1,000 men on each side.
Gen Itno was commanding the military operation launched 10 days ago against the rebels.
"Gen Abakar Youssouf Mahamat Itno has died of his injuries," an unnamed military source told Reuters news agency.
"Caught without communications, the general was surprised by the rebels who seriously wounded him," the source added.
The start of the operation came a week after the Chadian government said it had foiled a coup attempt against President Deby.
In December, Chad declared a state of war with Sudan following a deadly attack launched from Darfur by Chadian rebels.
Sudan repeatedly denied allegations made by Chad that it was backing the rebels and sending Arab militias in support.
In February, Chad and Sudan signed an accord to resolve their differences over fighting along the border.
Mr Deby seized power in 1990 after launching a rebellion from bases in Darfur.