Nigerien President Mahamadou Issoufou has replaced the head of the army after two of the country’s deadliest attacks in living memory killed at least 160 soldiers and prompted a rethink in the battle against jihadist groups, the government said. Ahmed Mohamed led the army for over two years, a period marked by a steep rise in attacks by militants linked to Islamic State and al Qaeda that culminated in a daytime raid on a remote army base on Thursday that killed at least 89 soldiers. That attack came less than a month after another on an outpost that killed 71 soldiers and raised questions about Niger’s ability to contain the spread of jihadist groups across its western border from Mali and Burkina Faso. Major General Salifou Modi was appointed Mohamed’s successor on Monday, the government announced after a cabinet meeting. Niger said it would launch a new military offensive against militants, but past campaigns have failed to curb violence despite the presence of French and American troops. Attacks in Niger have risen fourfold over the past year, killing more than 400 people, according to the Armed Conflict Location & Event Data Project, a non-profit research organization. Military campaigns by armies in the Sahel, a semi-arid swathe of land beneath the Sahara, have also been marred by human rights abuses, which analysts say have pushed some civilians into the arms of the jihadists. In addition to the Islamist attacks, countries in the region, especially Mali and Burkina Faso, have struggled to cope with deadly ethnic clashes between rival farming and herding communities.