Japanese archaeologists said Wednesday they have discovered in southern Egypt what they believe to be one of the largest quarries used in ancient Egypt.

Extending some 6 km, the quarry was found in a hilly section overlooking the Nile River near the Akoris ruins, a city that flourished from 2300 B.C. to 700, they said.

The quarry is believed to have been in full production in the first and second centuries, a period when Egypt was under Roman rule and numerous cities were established, they said. Limestone quarrying is still being conducted near the site.

The quantity of quarried stone used during the period may be more than was used to build the pyramids, which are generally believed to have been built around 3200 B.C., they said.

"By using the periodic flooding of the Nile River, quarry stones were transported throughout Egypt by water. The stones were probably used in building temples and paving roads," said Hiroyuki Kawanishi, a professor of archaeology at Tsukuba University in Ibaraki Prefecture.