The stunning announcement came just hours after electoral officials had declared Deby, 68, the winner of the April 11 presidential election, paving the way for him to stay in power for six more years.
An 18-month transitional council will be led by Deby’s 37-year-old son, Mahamat Idriss Deby Itno, the military said, also imposing a nightly curfew of 6 p.m.
“In the face of this worrying situation, the people of Chad must show their attachment to peace, to stability and to national cohesion,” Gen. Azem Bermandoa Agouma said.
The circumstances of Deby’s death could not immediately be independently confirmed due to the remote location of the fighting.
The military said Deby had taken “the heroic lead in combat operations against terrorists who had come from Libya.” After being wounded in battle, he then was taken to the capital, the general announced.
Deby, a former army commander-in-chief, first came to power in 1990 when his rebel forces overthrew then-President Hissene Habre, who was later convicted of human rights abuses at an international tribunal in Senegal.
Over the years Deby had survived numerous armed rebellions and managed to stay in power until this latest insurgency led by a group calling itself the Front for Change and Concord in Chad.
The rebels are believed to have armed and trained in neighbouring Libya before crossing into northern Chad on April 11. Their arrival came on the same day that Chad’s president sought a sixth term on election day, which several top opposition candidates boycotted.
Deby was a major French ally in the fight against Islamic extremism in Africa, hosting the base for the French military Operation Barkhane and supplying critical troops to the peacekeeping effort in northern Mali.
Deby’s son, Mahamat, has served as a top commander for Chadian forces taking part in that effort.