Archaeologists in Egypt say they have discovered what might be the oldest human footprint ever found.
The outline was found imprinted in mud, which has since turned to stone, at Siwa oasis in the western desert.
"This could go back about two million years," antiquities council chief Zahi Hawass was quoted by Reuters as saying.
However Khaled Saad, director of pre-history at the council, said it could be older still, and pre-date Ethiopia's 3m-year-old skeleton, Lucy.
Lucy, discovered in 1974 in Hadar, Ethiopia, is an extinct Australopithecus afarensis hominid estimated to be 3.2 million years old.
Creatures of her kind are assumed to have left the feet impressions recorded in volcanic ash at Laetoli in Tanzania. These prints have been dated to 3.6 million years ago.
The oldest footprints (and handprints) known to be associated with Homo (human) species are recorded in volcanic rocks at Roccamonfina in Italy. These are about 350,000 years old.
Commenting on the new discovery - which has yet to be reviewed by independent scientists - Mr Hawass said: "It could be the most important discovery in Egypt."
Until now the earliest evidence of human activity found in Egypt, most famous for the era of the pharaohs, dates from about 200,000 years ago.