The car bomb attack on Wednesday in Gao, the region's biggest city, targeted a camp housing former rebels and pro-government militia who are signatories to a 2015 peace accord struck with the government.
President Ibrahim Boubacar Keita ordered three days of national mourning following the attack, the worst in the country in recent years.
The group of Algerian jihadist and Al-Qaeda ally Mokhtar Belmokhtar claimed responsibility, in a statement, for the suicide bombing.
The group, allied to Al-Qaeda in the Islamic Maghreb (AQIM), identified the attacker as Abdelhadi al-Foulani, in a statement cited by the US-based SITE watchdog and Mauritanian news agency Al-Akhbar.
Defence Minister Abdoulaye Idrissa Maiga swiftly headed to Gao following the blast.
The attack occurred as former rebels from the Tuareg-led CMA movement prepared to go on a joint patrol with pro-government militia members, under the terms of the peace deal.
