CAIRO (AP) — Egypt's antiquities ministry says archaeologists have found a "giant fence" at the site of an ancient capital city in the northern Nile Delta region, dating back over 3,500 years.

Antiquities Minister Mamdouh el-Damaty said on Tuesday the discovery was made by the Austrian Archaeological Institute. He did not say when the discovery was made.

He says the fence, from the pharaonic Middle Kingdom, may have been part of a city's wall. The period coincided with the invasion of Egypt of the Hyksos, an ancient Asiatic people.

The ministry says the structure was found in Tal el-Dabaa in Sharqiya province, where Egypt's capital of Avaris was located at the time.

Antiquities official Mahmoud Afifi says it's at least 500 meters (yards) long and 7 meters (yards) thick, made out of sandstone.