EFETucson, US

Footprints found in New Mexico could be evidence of the earliest human presence on the American continent, 10,000 years earlier than previously believed, the University of Arizona said on Thursday.

Footprints found in White Sands National Park provide evidence of human activity in the Americas over 23,000 years ago. The findings were published in the Science journal.

"For decades, archaeologists have debated when people first arrived in the Americas. Few archaeologists see reliable evidence for sites older than about 16,000 years. Some think the arrival was later, no more than 13,000 years ago by makers of artifacts called Clovis points," said University of Arizona archaeologist Vance Holliday, who co-authored the Science journal article.

"The White Sands tracks provide a much earlier date. There are multiple layers of well-dated human tracks in streambeds where water flowed into an ancient lake. This was 10,000 years before Clovis people," he added.