The material found, including 1,900 carved stone tools, are a sample of a human occupation in the Chiquihuite cave, north of Mexico City, dating back 33,000 years, and lasting 20,000 years, two published studies highlight in the journal Nature.

Our investigations provide new evidence on the age of humans in the Americas, archaeologist Ciprian Ardelen, author of one of the two studies, told AFP.

The oldest utensils found in this cave, located at altitude, were carbon 14 dated in a range between 33,000 and 31,000 years before the Christian era.

There is not a lot, but it is there, said this researcher from the Autonomous University of Zacatecas.

While no bone or DNA was found at the site, it is likely that humans used it relatively consistently, perhaps during recurrent seasonal episodes that are part of larger migration periods, the study concludes.

The story of how and when Homo Sapiens came to the Americas - the last great landmass populated by the human species - is often the subject of debate among experts.