Chad's army said Monday it had killed more than 300 rebels following a heavily armed group's incursion in the country's north after election day.
"A military council has been set up headed by his son, General Mahamat Idriss Deby Itno", the army's spokesman, General Azem Bermandoa Agouna, said on state radio.
"A call to dialogue and peace is launched to all Chadians in the country and overseas in order to continue to build Chad together", Agouna said.
The Chadian army has said a military council led by the late president's 37-year-old son Mahamat Idriss Deby Itno, a four-star general, would replace him.
Under Deby's leadership, Chad together with Benin, Cameroon, Niger and Nigeria formed a Multinational Joint Task Force, mandated by the African Union Peace and Security Council in 2015 with the support of external partners.
Chad's military claimed that it has killed some 300 rebels advancing on the capital, N'Djamena, as the government on Monday deployed tanks and other armed vehicles in the city's streets.
On Monday, provisional results from the election on 11 April projected he would win a sixth term in office, with 80% of the vote.
In the Tibesti massacre along the border with Libya, rebels regularly confront the Chadian army.
But he faced mounting discontent at home over his management of Chad's oil wealth, crackdowns on opponents and alleged corruption.
Chad, a French colony until independence in 1960, has become a powerful French ally in the fight against Islamic extremism in Africa under Deby's tenure.
"This probably aims to counter any coup-making efforts from within the security establishment and to reassure Chad's global partners - especially France but also the United States - that they can still count on the country for its continued contributions to worldwide counter-terrorist efforts in the Sahel".
Some residents of the capital, though, said they feared there was more to the story of Deby's demise.
"That in itself is a coup", the diplomat told Reuters.
He seized power in 1990, leading a rebel army swathed in desert headgear in a three-week offensive launched from neighbouring Sudan to topple Habré, a man accused of instigating tens of thousands of political murders. "It raises concerns regarding the security forces' assessment of the clashes and their intelligence regarding the severity of the situation".