General Mahamat Kaka, the son of the deceased Chadian president, has been named interim head of the state, Army spokesman announced this on Tuesday.
Mr Deby died on Tuesday of injuries he sustained on frontline.
The news came a day after Deby, who came to power in a rebellion in 1990, won a sixth term, as per provisional results released on Monday. Deby took 79.3 percent of the vote in the April 11 presidential election, the results showed.
Deby postponed his victory speech to supporters and instead went to visit Chadian soldiers battling rebels, according to his campaign manager.
The rebel group Front for Change and Concord in Chad (FACT), which is based across the northern frontier with Libya, attacked a border post on election day and then advanced hundreds of kilometres south.
But it suffered a setback over the weekend.
Chad’s military spokesman Agouna, told the Reuters news agency that army troops killed more than 300 fighters and captured 150 on Saturday in Kanem province, around 300 kilometres (185 miles) from the capital Ndjamena.
Five government soldiers were killed and 36 were injured, he said.
