An Algerian military transport plane has crashed in the north-east of the country, killing all but one of the 78 people on board.

The Hercules C-130 crashed into a mountain in Oum al-Bouaghi province, en route to Constantine, in bad weather conditions.

One survivor is being treated for head injuries, reports said.

The government and military say 78 people were on board - not 103 as reported by officials and local media.

Most of those on board were military personnel and their family members.

"I saw the military plane crashing, and it was cut into two pieces," a firefighter, Mohamed, told Reuters news agency at Ouled Gacem, near the crash site.

Women and children were among the 77 bodies recovered from the crash site.

Dozens of rescue workers reached the scene, despite the mountainous terrain and wintry weather conditions.

Ambulances take the bodies of the crash victims from the crash site in Oum al-Bouaghi province

Onlookers watched rescue workers who flooded to the crash site despite the mountainous terrain and cold conditions

The president paid homage to those on board - mainly military personnel and their families - as "martyrs"

President Abdelaziz Bouteflika sent his condolences to families of the "martyrs" and has decreed three days of national mourning to begin on Wednesday, said state TV.

'Storm and snowfall'

The plane was originally reported to have been carrying 99 passengers and four crew members.

Its departure point was the Sahara Desert garrison city of Tamanrasset, 1,500km (950 miles) south of Constantine. It made a stop in Ouargla.

A source told radio station Ennahar - which has close links to the government and army - that contact was lost with the military plane between Oum al-Bouaghi and Constantine as it was descending to land.

It crashed into Djebel Fertas mountain, some 380km (240 miles) east of the capital Algiers.

"The plane crashed into a mountain and exploded. Several bodies were burnt to ashes and could not be identified," an official told Reuters.

The defence ministry said it had set up a commission to investigate the crash and that Ahmed Gaid Salah, who is both army chief of staff and deputy defence minister, would go to the crash site, Reuters reported.

In a statement, the defence ministry blamed "very bad weather conditions, involving a storm and heavy snowfall", for the crash.

This is the worst plane crash in Algeria for more than 10 years and the third involving an Algerian military Hercules.

An Air Algerie Boeing 737 crashed on take-off from Tamanrasset in 2003, killing all but one of the 103 people on board.