Celebrations of the ancient festival were marred by clashes with security forces who came to blows with revellers and reports that 19 had died and 5,000 were left injured.
There are no details on whether any of the injuries were caused by security forces who used tear gas and force to disperse crowds in some areas and most incidents occurring in the provinces of Tehran, West Azarbaijan, and East Azarbaijan.
Videos circulating on social media showed large crowds gathering in cities like Tehran, Karaj and Rasht, with bonfires illuminating the night sky and the sounds of music and cheering filling the air.
The festival, marked by jumping over bonfires and setting off fireworks, is a deeply rooted cultural tradition, but it has increasingly become a flashpoint for defiance against the Islamic Republic's restrictions.
The celebrations went ahead with full force in spite of the government warnings against celebrations, young people seeing it as an expression of their cultural identity and a way to challenge authority.