(CNN) -- One person survived the crash of a military plane Tuesday in the mountains of eastern Algeria that left at least 77 others dead, a spokeswoman for the country's Civil Protection office said.
The spokeswoman, who could not give her name in line with protocol, said there were a total of 78 people on board the plane. The man who survived has head injuries and was taken to a hospital, she added.
Algerian President Abdelaziz Bouteflika declared a three-day national mourning period and offered his condolences to the families of the victims, the state-run Algerie Presse Service (APS) reported.
The Hercules C-130 was carrying members of the Algerian air force and their families, according to several media outlets in Algeria.
Initial reports on the crash gave conflicting numbers, with some saying 103 people were on board the aircraft and as many as 100 had died. Others cited 52 deaths and more than two dozen missing.
The plane was flying from Tamanrasset in southern Algeria to Constantine in the east, the Defense Ministry said in a statement.
"An investigative team has been created and sent to the scene to determine the cause and the exact circumstances of this tragic accident," the Defense Ministry statement said, adding that top military officials were heading to the crash site.
The plane crashed in Mount Fertas, which is about 500 kilometers (310 miles) east of Algeris, according to APS.
State radio, citing a military source, said bad weather was behind the crash.
There was a snowstorm in the area when the plane went down, witnesses told the radio network.