About 100 militants ambushed an army camp in western Niger, a military spokesman said late Wednesday, killing at least 71 soldiers in the deadliest attack on the West African country's forces in years.

The large-scale attack came amid a surge of assaults on army camps in the Sahel region, which have allowed militants to amass weapons and vehicles for their arsenal. Neighboring Mali has seen such an increase in ambushes on its army that it has even closed some of its most remote and vulnerable army outposts.

Niger's army spokesman, Col. Boukar Hassan, read the death toll announcement on state television Wednesday night and said a dozen others had been wounded after the ambush overnight.

The large attack took place in a remote area of Niger where militants linked to the Daesh terrorist group have long been active. The violence was 30 miles (45 kilometers) from Ouallam, where four U.S. service members died along with four Nigerien soldiers two years ago when their joint patrol came under fire in a massive ambush. Daesh has long carried out attacks across the vast desert region, abducting foreigners and targeting spots popular with expatriates. A regional military force and a French military mission have failed to stem the violence.

Given the growing insecurity, Mali's military has closed some of its most isolated and vulnerable outposts as part of a reorganization. Amid growing anti-French sentiments in the region, France's operation in West and Central Africa is now its largest overseas military mission and involves 4,500 personnel. France intervened in Mali in 2013 after Daesh seized control of major towns in the north and implemented a harsh version of Islamic law.