Boko Haram terrorist group killed 92 Chadian soldiers in attack on an island in Lake Chad.
President Idriss Déby said on a visit on Thursday to the area that the raid was the terrorists’ deadliest yet in Chad.
Lake Chad is the region where forces from Chad, Nigeria and Niger have been fighting the militants in a joint campaign for the last five years.
According to military sources, the attack was on an army base on the island of Boma and lasted for seven hours.
Weapons were captured by the insurgents, who escaped with them in speedboats, they said.
Nigeria also experienced a deadly attack on Monday, when 47 soldiers were killed in a Boko Haram ambush.
The Boko Haram militia began in north-eastern Nigeria a decade ago – and the violence has spread to neighbouring countries, killing more than 30,000 people and forcing two million from their homes, according to the UN.