The remains of 79 human bodies dating back to the seventh century have been found at a fortress in Peru.

The human remains were found inside a stone wall believed to have been a grave site in the Kuelap fortress, said Alfredo Narvaez, director of the conservation project.

However, the grave site must have been a secondary burial place, meaning the remains had been removed from their original place. Those involved in building the fortress brought the dead from their original graves to Kuelap for reburial, Narvaez said.

'This custom is widespread in pre-Columbian Peru and required the community efforts of people from several areas,' he said.

'Most are bone remains are of adults, but we're not ruling out that there may also be remains of adolescents,' he said.

The 1000 A.D. Kuelap complex comprises 400 buildings, but the difficulty in accessing this archaeological site has prevented it from being an important tourist destination.