Chad's President Idriss Deby Itno has died in combat after three decades in power, the army said on Tuesday, opening a period of uncertainty in a country that is a key strategic ally of the West in a troubled region.
His son was immediately named transitional leader as head of a military council and both the government and parliament were dissolved, but the army vowed "free and democratic" elections after an 18-month transitional period.
The army said Mr Deby had died from injuries sustained as he led his troops against rebels who launched an offensive against his regime from Libya last week.
Chad had claimed victory against the fighters, but soon after the announcement of Mr Deby's death, they vowed to pursue their offensive and march on the capital N'Djamena.
The shock news came just a day after the 68-year-old career military man was proclaimed the winner of a presidential election that gave him a sixth term in office.
Idriss Deby Itno, centre-right, meets with French Defense Minister Herve Morin, centre-left, in 2008. Source: AFP
The army also announced a curfew and border closures, while a state funeral was planned for Friday.
Mr Deby, often called "marshal," had ruled Chad with an iron fist since taking power on the back of a coup in 1990, and often put members of his family and ethnic group in key positions in government and the military.
'Essential ally'
He was nonetheless a key ally in the West's anti-jihadist campaign in the unstable Sahel region, particularly due to the relative strength of Chad's military and its ability to supply weaponry and soldiers.
Former colonial power France hailed Mr Deby as an "essential ally in the fight against terrorism" and called for a peaceful transition over a limited timeframe.
The United States offered condolences and said it supported "a peaceful transition of power in accordance with the Chadian constitution".
In this 28 August file photo, Chadian President Idriss Deby poses with France's President Emmanuel Macron. Source: AAP
The European Union said Chad had lost "a "historic political figure" and that the "announced transition must be limited, take place in a peaceful manner... and allow for the organisation of new inclusive elections".
Following the announcement of Mr Deby's death, presidential guard officers in civilian clothes roamed N'Djamena with walkie-talkies and handguns.
Police in black uniforms and masks were also on the streets, although the military presence was no more intensive than since the rebel offensive began in northern Chad on 11 April, the day of the presidential election.
'Defending the nation'
The army said Deby had been commanding his forces at the weekend as they battled rebel group Front for Change and Concord in Chad (FACT).
Mr Deby "has just breathed his last breath defending the sovereign nation on the battlefield," army spokesman General Azem Bermandoa Agouna said in a statement read out on state television.
He said Deby had died on Tuesday, but the presidency later gave the date as Monday.
The army 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.
Mr Deby's son oversaw his father's security as head of the elite presidential guard and often appeared alongside him, wearing the force's red beret, dark glasses and military fatigues.
He signed a decree on Tuesday setting out a military council with 15 generals, including himself and 14 others known to have been part of the late president's circle of loyalists.
Some analysts expressed concern that Mr Deby's death could unleash new rounds of violence.
On Monday, the army claimed a "great victory" against FACT, saying it had killed more than 300 rebels and captured 150 others, with the loss of five soldiers.
But FACT spokesman Kingabe Ogouzeimi de Tapol told AFP that the rebels would continue the offensive after a short delay for Mr Deby's funeral.
"We categorically reject the transition," he said.
Ministers and high-ranking military brass had said Monday that Mr Deby was in the region on Saturday and Sunday after the rebel offensive.
Mr Deby, who had been among the world's longest-serving leaders, had on previous occasions gone to the frontlines as government forces battled rebels.
Provisional results released on Monday showed him winning re-election with almost 80 per cent of the vote.
His victory had never been in doubt, with a divided opposition, boycott calls, and a campaign in which demonstrations were banned or dispersed.
A file photo of President of Chad Idriss Deby. Source: AAP
Herder's son
Mr Deby was a herder's son from the Zaghawa ethnic group who took the classic path to power through the army.
He had campaigned for the latest election on a promise of bringing peace and security to the troubled region, but his pledges were undermined by the rebel incursion.
The government had sought on Monday to assure concerned residents that the offensive in the provinces of Tibesti and Kanem was over.
But much remains unclear regarding the rebel action, which had led several nations including the US and Britain to advise their nationals to leave.
One analyst said the country was "entering uncharted territory".
"A damaging succession crisis is to be feared, while government forces and rebels have been fighting each other in the north and centre of the country," said Richard Moncrieff of the International Crisis Group think tank.
