One of Chad's top army officers has been killed in fighting with rebels in a battle near Chad's border with Sudan.
The army has been unable to end the rebellion
Gen Moussa Seugui died after being shot in the shoulder in the south-eastern town of Hadjer Meram, Defence Minister Bichara Issa told the BBC.
The general was taken to hospital but doctors were unable to save him.
Mr Issa said the army had lost four of its men and claimed 100 rebels had been killed although there is no independent confirmation of the figures.
The BBC's Stephanie Hancock in Chad has been told by military sources that casualties from the fighting were extremely heavy and the actual number may be far higher.
The fighting is part of a week-long offensive by rebels of the recently-formed Union for the Forces of Development and Democracy.
They have been moving through a series of towns in eastern Chad, clashing with government forces from time to time. Both sides say they have the upper hand in the fighting.
"The humanitarian fallout is extremely serious," UN Undersecretary-General for Peacekeeping Jean-Marie Guehenno has warned.
As well as clashes between Chadian soldiers and rebels intent on overthrowing President Idriss Deby, relations between Chad and Sudan have also deteriorated.
Last week, Chad accused Sudan of backing the rebels, and on Saturday accused Khartoum of bombing villages in eastern Chad - a charge Sudan has denied.
Sudan in turn accuses Chad of backing rebels in its war-torn Darfur region, which has a similar ethnic make-up to eastern Chad.
In April, a rebel advance reached the capital, N'Djamena, before being pushed back.