Oumar Traore, chief of staff of Colonel Assimi Goita, was killed in the ambush some 400 kilometers north of the capital Bamako near the Mauritanian border, in an area known for jihadist insurgents.
Traore was part of an official delegation that had travelled to the area, near the town of Nara and the Wagadou forest, to scout prospective drilling sites for local populations.
The document identifies three other victims including a security guard, a contractor and a driver.
Another driver is missing, it said.
The attack has not yet been claimed.
Mali has been battling a security and political crisis since jihadist and separatist insurgencies broke out in the north of the country in 2012.
Since 2020, it has been ruled by a military junta now led by Colonel Assimi Goita. Under international pressure, it has pledged to respect a return to democracy by March 2024.