A secret-passageway dating back 3,300 years has been discovered in central Turkey.

At the Alacahoyuk archaeological site in central Turkey, one of the sites of the ancient Hittite settlements, archaeologists excavating a sanctuary that had been discovered two years ago came across the ancient tunnel.

Speaking to Hurriyet Daily News, Aykut Cinaroglu, the head of excavations and professor at Ankara University, said the discovery of the secret passageway, known as a potern, is a significant discovery on the site.

“This is a big discovery in terms of Hittite architecture. This is my 55th year in my professional life. I never thought I would find a potern but I did,” he said.

Alacahoyuk was known as the religious capital for the Hittites, an ancient Anatolian people who ran an empire around 1600 BC. The former capital of the empire, Hattusha, is a Unesco archaeological site in modern day Turkey where temples, royal residencies and fortifications have been discovered.

Mr Cinaroglu said poterns were usually placed under a castle and extended out into the city. He said he believes there will be other poterns in the area, and that his team have dug 23 metres worth of the secret tunnel so far but that they believe it is longer.

“We have previously found a cuneiform [form of ancient script] tablet here, featuring a king who explains to priests what to do during ceremonies. This secret tunnel may have a sacred function.”