Archaeologist Davud Abyan said the recent discovery proved that the site was older than previously estimated.

“Shards from the Achaemenid era had been found at the site before, and the recent finding revealed the first signs of the Achaemenid dynasty,” he said.

The site also contains ruins from the Sassanid and Parthian eras, and the most recent discovery of the five tepes further confirmed that it was a significant site in the pre-Islamic era, he added.

Since the region is very fertile, the surrounding land has been cultivated by farmers, leading to the destruction of ancient ruins, and the five tepes are the only ones remaining, he stated, adding that the studies would be completed in late October and that emergency excavations would resume afterwards.

The names of the tepes were not announced due to the threat of smuggling.

Situated in Zanjan Province, the Soltanieh Dome, the mausoleum of Oljaitu, was constructed from 1302 to 1312 in the city of Soltanieh, the capital of the Ilkhanids, Mongol descendents of Genghis Khan who controlled large parts of Iran from 1256 to 1349.

Soltanieh was registered on the UNESCO World Heritage List on July 15, 2005 during the 29th Session of the World Heritage Committee, which was held in Durban, South Africa.