An attack by jihadist group Boko Haram killed around 40 Chadian troops overnight near the Nigerian border, prompting an army operation to hunt down the militants, the government and local sources said on Monday.
Members of Boko Haram targeted a garrison housing more than 200 Chadian soldiers late Sunday in the Lake Chad region, an area plagued by various armed groups, local sources told AFP.
The presidency said in a statement that the attack struck near Ngouboua in the west of the country, "tragically leaving about 40 people dead".
Chadian President Mahamat Idriss Deby Itno visited the scene early on Monday and launched an operation "to go after the attackers and track them down in their furthest hideouts", the statement added.
The garrison's unit commander was among the dead, a high-ranking officer said on condition of anonymity.
The assailants "had time to seize ammunition and equipment before they retreated", the officer added.
Around 20 people were also wounded, military sources said.
"Boko Haram members took control of the garrison, seized the weapons, burnt vehicles equipped with heavy arms, and left," said one local source, who asked not to be named.
The surprise attack struck a Chadian army position near the Nigerian border late on Sunday evening, military sources said.
"We have many casualties, yes, but the situation is under control and our forces are on the ground pursuing the enemy," the regional governor, General Saleh Haggar Tidjani, told AFP.
In a vast expanse of water and swamps, the Lake Chad region's countless islets serve as hideouts for jihadist groups, such as Boko Haram and its offshoot Islamic State in West Africa (ISWAP), who make regular attacks on the country's army and civilians.
Boko Haram launched an insurgency in Nigeria in 2009, leaving more than 40,000 people dead and displacing two million, and the organisation has since spread to neighbouring countries.
In March 2020, the Chadian army suffered its biggest ever one-day losses in the region, when around 100 troops died in a raid on the lake's Bohoma peninsula.
The attack prompted then-president Idriss Deby Itno -- the current president's father -- to launch an anti-jihadist offensive.
The current president "would like to reassure the population in the area as well as defence and security forces of his unwavering commitment to defend and secure the entire country", the presidency added in Monday's statement.
The International Office for Migration in June recorded more than 220,000 people displaced by attacks from armed groups in Lake Chad province.
The Chadian leader recently reshuffled the leadership of the armed forces, a move sources said was linked to some officers' opposition to his stance on the war in Sudan.
N'Djamena has been accused of channelling weapons from the United Arab Emirates (UAE) to the Sudanese paramilitary Rapid Support Forces, a militia that has been fighting against the Sudanese army for over a year.
Both the UAE and Chad have denied the accusations.
The Sudan conflict has left tens of thousands dead and displaced millions, according to the United Nations.
