Hardik Patel and his supporters were detained on Sunday when they were trying to organise fast in Ahmedabad's Nikol area.
Sunday's symbolic fast was aimed at seeking allocation of a ground for a gathering planned by Hardik Patel. On August 25, Patel planned a protest in order to press for his demand for quota for Patidar youths in jobs and education.
Hardik and eight leaders of the (Patidar Anamat Andolan Samiti) PAAS were detained on Sunday by the city crime branch from outside his house in Sola area, said Crime Branch DCP Deepan Bhadran, reported news agency PTI.
The Crime Branch has registered an FIR against Hardik and eight others under sections 143 (Unlawful assembly) and 186 (Obstructing public servant in discharge of public functions) of the IPC, news agency further reported.
Hardik and others were detained from outside Hardik's house for unlawful assembly and other charges.
Gujarat Pradesh Congress president Amit Chavda and Leader of Opposition Paresh Dhanani condemned the sudden action by the cops.