Iranians across the country are commemorating the 52nd anniversary of an uprising against the US-backed former monarchical�regime of Pahlavi.
People are marking the day, known as 15th of Khordad on the Iranian calendar, in different parts of the country.
To the Iranians, the event marks a prelude to the victory of Iran�s Islamic Revolution in 1979.
In 1963, a massive crowd of people took to the streets to protest against the arrest of the late founder of the Islamic Republic Ayatollah Rouhollah Khomeini by the Pahlavi regime�s security forces.
Imam Khomeini had been arrested for his angry speech against the ruling Shah and the US.
A large number of people were killed by the police and the military during the violent crackdown on protesters in different cities.
Fifteen years later, Imam Khomeini spearheaded Iran�s 1979 Islamic Revolution, which led to the overthrow of the US-backed Shah of Iran.
Iranians mark the event annually since the victory of the Islamic Revolution.
The occasion, which falls on June 5th�this year, is a national holiday in Iran.