Iran blocks 'illegal' rally at ancient king's tomb
The intelligence ministry had identified members of "a counter-revolutionary group which had wanted to organise an illegal gathering under the pretext of celebrating Cyrus," the Mizanonline news website reported.
Authorities on Saturday cut the main highway between the cities of Shiraz and Esfahan, which leads to an archaeological site where the tomb is believed to be located.
They said the closure was for road work.
Semi-official ISNA news agency reported that the head of the elite Revolutionary Guard, General Hashem Ghiassi, had issued a warning on Saturday to the "counter-revolutionaries".
Authorities in Iran last October arrested several organisers of a rally at the same site.
Footage posted on social media showed participants chanting for freedom of expression, along with nationalistic and anti-Arab slogans.
Authorities later said they had arrested a number of rally organisers "for having violated norms and chanting slogans against the values" of the Islamic republic of Iran.
Cyrus the Great was the founder of the Achaemenid Empire in the 6th century BC and ruled over ancient Persia for about 30 years.
So-called "Cyrus Day" rallies are held on October 29 to mark the king's capture of Babylon in 539 BC.
Iran's last shah Mohammad Reza Pahlavi, who was ousted by the 1979 Islamic revolution, had claimed to be a descendent of Cyrus.