Boffins unearthed a "war grave" where the remains of 27 people lay.
Each of the victims had received horrific abuse before their harrowing death.
Experts believe the massacre took place more than 10,000 years ago.
Women, children and men were clubbed and stabbed to death by savages who attacked their settlement.
Victims of the bloody battle were found with their hands bound with their damaged bones showed signs of violent deaths.
The discovery was made at a remote region in Nataruk, Kenya, where a large population of nomadic hunter-gatherers settled.
The site is also believed to be the first evidence of human warfare.
Boffins are startled by the findings which show large-scale armed conflict used to settle disputes originated thousands of years before previously thought.
Lead researcher Dr Marta Mirazon Lahr, from Cambridge University's Leverhulme Centre for the Study of Human Evolution, said: "The deaths at Nataruk are testimony to the antiquity of inter-group violence and war.
"These human remains record the intentional killing of a small band of foragers with no deliberate burial, and provide unique evidence that warfare was part of the repertoire of inter-group relations among some prehistoric hunter-gatherers."
The site was first unearthed in 2012.
However it has taken years for scientists to date the remains accurately.
The origins of war remain controversial among experts.
Many believe it developed with the emergence of agriculture and settled communities around 6,000 years ago.
(dailystar.co.uk)
www.bakuinfo.az
