The toll for the crash of an Algerian military transport plane has been reduced to 76 dead and one survivor, a civil defence spokesman said Wednesday.

Lt. Nassim Bernaoui of Algerian Civil Defence said the military plane carried a total of 77 people, not 78.

After radio and radar contact with the flight was lost at 11:37 a.m. local time on Tuesday, three helicopters were sent to find the plane. The ministry said it had slammed into Mount Fortas, 50 kilometres from the flight's destination city of Constantine.

The lone survivor — a soldier — suffered head injuries and was treated at a nearby military facility before being flown to the military hospital in Algiers, the capital, a retired intelligence officer told the AP. He spoke on condition of anonymity because he was not authorized to speak to the press.

Initial reports from both Algerian government officials and Algerian media had said that 103 people including four crew had been on the plane. That was later reduced to 78 people, then 77.

APTOPIX Algeria Plane Crash

A man watches rescue workers working at the wreckage of Algerian military transport aircraft after it slammed into a mountain in the country's rugged eastern region on Tuesday. (Mohamed Ali/Associated Press)

The Defence Ministry, meanwhile, blamed the weather. 
"Unfavourable weather conditions and storms accompanied by snow in the region were behind the crash," the ministry said in a statement.

Winds in the area were 31 km/h gusting to 51 km/h with a visibility of eight kilometres at the time, according to the website.

The presidency announced a three-day period of mourning, calling the soldiers who had died "martyrs for the country."

The worst plane crash in Algerian history occurred in 2003, when 102 people were killed after a civilian airliner crashed at the end of the runway in Tamanrasset. There was also a single survivor in that crash.