The oldest stone axe tools ever found in Asia have been unearthed by a team of Chinese and American archaeologists.

The tools, which are about 803,000 years old, demonstrate that early humans living in the region had a similar degree of technological expertise as those living in Africa.

Until now it had been suggested that early Asian humans were not as sophisticated as those living on the African continent and in Europe during the same time period.

The tools were uncovered in the Guangxi Zhuang Autonomous region, near the border with Vietnam in southern China. They are classic hand-held stone axes - teardrop shaped with a sharp cutting edge.

Devastating event

They were found alongside tiny scraps of charcoal and tektites - little pieces of glassy rock formed when a meteorite impact melts terrestrial rock.

These were used to date the tools. It is thought that about 800,000 years ago a massive meteor hit the Earth, laying large areas of what is now South East Asia to waste and setting huge areas of forest on fire.

Dr Rick Potts, from the Smithsonian Institution in Washington DC, US, and one member of the research team, said no-one knows whether the meteor hit the ground and broke up, or exploded just above ground level. Either way, the event was devastating.

"It would have killed off life close to the impact area or entry area. It must have been an awful place to have been at the time," he said.

Dr Potts' team, which includes researchers from the Chinese Academy of Sciences in Beijing, believe that one way in which the early humans responded to the catastrophe was by learning to make stone axes.

The whole story

Most researchers agree that the first humans to make tools lived in Africa. Very simple implements have been recovered there that are about 2.5 million years old. About a million years later, the more sophisticated teardrop-shaped tools began to emerge.

These have also been found in Europe, but have never before been found and reliably dated in Asia. For this reason, some researchers had suggested that Pleistocene (about 500,000 to one million years ago) Asian populations were not as advanced as their Homo erectus counterparts further west.

But Rick Potts believes that this discovery emphasises the need to look at all parts of the world to piece together the story of how we came to be.

"The early humans in China, in eastern Asia, were not part of some cultural backwater," he said. "They had the competence and the smartness to do exactly what hominids were doing in other parts of the world."

The discovery is reported in the journal Science.