Chad will bury veteran ruler Idriss Deby Itno on Friday as concerns mount over the loss of a lynchpin in the fight against jihadism in the Sahel and uncertainty over the country's democratic future.
President Emmanuel Macron of France, the former colonial power, will attend the ceremony along with a dozen other heads of state and EU foreign policy chief Josep Borrell.
The funeral, complete with military honours, is scheduled to take place in the morning in N'Djamena's main square, La Place de la Nation.
The ceremony is to be followed by prayers at the capital's Grand Mosque, after which Deby is to be laid to rest alongside his father in the village of Amdjarass next to his birthplace Berdoba, in the far east of the desert country near the border with Sudan.
Chad, with a well respected fighting force, is central to the West's fight against jihadists in the Sahel, where myriad Islamist extremist groups operate.
France's 5,100-strong Barkhane anti-jihadist force is headquartered in N'Djamena, capital of the country of 16 million.
Chad was thrown into turmoil by Deby's death, which was announced on Tuesday, just the day after he was declared the winner of an April 11 election -- giving him a sixth mandate after 30 years at the helm.
Deby's re-election was never in doubt, with a divided opposition, boycott calls and a campaign in which demonstrations were banned or dispersed.
The army said Deby had died on Monday from wounds suffered while leading troops in battle against rebels who had launched an incursion from neighbouring Libya.
The Front for Change and Concord in Chad (FACT) has vowed to pursue its offensive after a pause for Deby's funeral, with spokesman Kingabe Ogouzeimi de Tapol telling AFP that the rebels were "en route to N'Djamena".
On Monday -- the day of Deby's reported death -- the army had claimed a "great victory", saying it had killed more than 300 FACT rebels and captured 150 others, with the loss of five soldiers.
- 'Institutional coup' -
Meanwhile allies of the late leader moved swiftly to ensure power remained in their hands, installing his 37-year-old son Mahamat, whose nickname is "Kaka", as president and head of a transitional military council while dissolving parliament and the government.
Following what the opposition called an "institutional coup d'etat", the transition period is meant to last 18 months and lead to democratic elections, though it can be extended once.
Deby came to power in 1990 and had twice thwarted attempted coups with support from France.
Macron, who met the younger Deby after arriving on Thursday evening, is the only western head of state to have announced plans to attend the funeral.
Other heads of state include those of immediate neighbours Mali, Niger and Burkina Faso, as well as Felix Tshisekedi of the Democratic Republic of Congo.
Macron's presence suggests that France will give a form of endorsement for his successor son at a time of turbulence, while also setting down parameters for a democratic transition, analysts say.
The funeral presents a major security challenge, with the junta under pressure from the opposition and the FACT rebels, as well as infighting.
Roland Marchal of the International Research Centre at the Sciences-Po school in Paris, warned that an all-powerful elite force called the DDGSSIE, headed by the young Mahamat Deby, "faces the risk of splitting."