National Anthropology and History Institute, or INAH, specialists have discovered five human footprints in northern Mexico's Sierra Tarahumara that could be between 4,500 and 23,000 years old, officials said.

The find took place in the northern state of Chihuahua after a local resident notified the authorities about the imprints, which were probably left by some of the first humans to populate that region of northern Mexico.

INAH said in a communique that these are "the first human footprints to be found" in Chihuahua and that if their antiquity is verified, "they will be added to the few footprints left by the earliest inhabitants of the American continent that are preserved in Mexico."

To date in Mexico footprints have been found in the municipality of Cuatro Cienegas in Coahuila state and on a ranch in the state of Sonora.

Two of the footprints correspond to the two feet of an adult, while the other three are of two adults and a child.

They all probably lived in caves in the Ahuatos Valley in the Sierra Tarahumara mountains, eight kilometers (11 miles) from the village of Creel in Chihuahua state, the institute said.

The largest footprint is 26 centimeters (10 inches) long and was made by an adult male, while the smallest measures 17 centimeters (7 inches) and corresponds to the right foot of a child 3 to 4 years old.

The two prints made by one person's feet have six toes each, "possibly due to a malformation," INAH said.

Anthropologist Jose Concepcion Jimenez said that a Chihuahua resident sent him an e-mail telling him of ancient footprints in the Ahuatos Valley in the municipality of Bocoyna.

"After several searches we found them in a stream running down an incline in a place of approximately 1,000 square meters (1/4 acre). The imprints are located in an area about 2 meters (6 1/2 feet) into the stream that only has water during the rainy season and is dry the rest of the year," he said.

The experts made a study of terrain extending 50 kilometers (31 miles) around the place and found "an area with traces of primitive campsites."

That has led the experts to believe that humans were present in the area from times as remote as the Pleistocene Epoch - 12,000 years ago.

The anthropologists also found five caves nearby with traces of human presence, three of them with several layers of cave paintings from three different periods: preceramic, pre-Hispanic and colonial.

Also found in the caves were soot from bonfires and holes carved into the rocks to be used as mortars for grinding food.

At the cave entrances specialists also detected a series of holes 25 centimeters (almost 10 inches) in diameter by 1.3 meters (4 1/4 feet) deep "that could have been used for storing food, as well as some smaller ones perhaps used to stick wooden posts into," the note said.

According to Jimenez, coordinator of INAH's Early Man in Mexico project, these discoveries are of great relevance because they indicate that this part of Chihuahua state was settled by "some of the first bands of human beings to arrive in this part of the continent."

The official said that some additional laboratory studies will be needed to assign an exact date to these human remains, cave paintings and other archaeological materials that have been found.

As of now the oldest human remains in the Americas are those of the so-called "Naharon woman," 11,600 years old, which were found in a cenote in the Mexican state of Quintana Roo.