
NAIROBI, Kenya — The rebels pulled off a stunning feat. Barely a week after their armed convoy roared across the desert into northern Chad, they kicked off a battle that on Monday claimed the biggest scalp of all: Idriss Déby, Chad’s iron-fisted president of three decades, killed on the battlefield when a shell exploded near his vehicle, according to a senior aide.
On Wednesday, a day after his death was announced, a sense of apprehension and disbelief reverberated through the capital, Ndjamena, where the military formally installed as interim president Mr. Déby’s 37-year-old son, Mahamat Idriss Déby. Rumors of an impending rebel attack on the city coursed through its streets.
But the secret of the rebels’ striking success thus far lay behind them, across Chad’s northern border in Libya, where they have been fighting as soldiers of fortune for years, amassing weapons, money and battlefield experience, according to United Nations investigators, regional experts and Chadian officials. In effect, the rebels used Libya’s chaotic war to prepare for their own campaign in Chad.
Khalifa Hifter, a powerful Libyan commander once championed by President Donald J. Trump. They fought with weapons supplied by the United Arab Emirates, one of Mr. Hifter’s main foreign sponsors.
spreading across western and central Africa.