Algerian state television says 77 people died when a military plane slammed into a mountain near the northern city of Constantine Tuesday.
Algeria's Defense Ministry said one person survived the crash and was undergoing treatment at a regional military hospital.
In a follow-up statement, the military said it had accounted for all 74 passengers and four crew - far fewer than the 103 people earlier reported to have been on board the doomed C-130 transport.
There was no immediate explanation provided for the discrepancy.
Official Algerian media linked the crash to bad weather, including snow and gale-force winds, and said President Abdelaziz Bouteflika has declared a three-day period of national mourning.
The reports say the flight originated in the southern province of Tamanrasset.