Chad’s longtime President Idriss Deby has died of wounds suffered on the front line in the country’s north, where he had gone to visit soldiers battling rebels, the armed forces said.

Deby, 68, “has just breathed his last defending the sovereign nation on the battlefield” over the weekend, army spokesman General Azem Bermandoa Agouna said in a statement read out on state television on Tuesday, a day after Deby was declared the winner of a presidential election.

The exact circumstances of Deby’s death were not immediately clear. The army said the president had been commanding his army at the weekend as it battled rebels who had launched a major incursion into the north of the country on Election Day on April 11.

Agouna also said a military council led by the late president’s 37-year-old son, four-star General Mahamat Idriss Deby, would replace him. A curfew has been imposed and the country’s borders have been shut in the wake of the president’s death.

“What the constitution says is that in the absence of the president or in case he dies, then the speaker of the parliament takes charge of the country for 40 days and so a transition is put in place until elections are held,” she said.

The shock announcement came a day after Deby, who came to power in a rebellion in 1990, won a sixth term. Provisional results released on Monday showed that Deby had taken 79.3 percent of the vote.

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 in the provinces of Tibesti and Kanem on Election Day and then advanced hundreds of kilometres south.