Police sources said people from many places in south Kashmir and parts of old Srinagar city took to the streets despite the strict curfew.
The government had tightened security across the valley to thwart the Anantnag march, fearing an outbreak of violent protests if people came out in large numbers to reach south Kashmir - the worst hit in the days of unrest that has left nearly 50 people dead and thousands injured.
The sources said police and paramilitary forces baton charged and fired pellets to chase away the protesters marching towards Anantnag town square where separatist leaders Syed Ali Shah Geelani and Mirwaiz Umar Farooq had planned to address public rallies and offer prayers in absentia for the dead.
Both Geelani and the Mirwaiz were taken into preventive custody as they defied prohibitory orders.
Geelani, who has been in detention at his residence in the upscale Hyderpora neighbourhood, came out despite a tight security cordon around his house. But policemen outside stopped him and drove him away in a bullet proof armoured vehicle to the nearby Humhama police station, an officer told IANS.
The Mirwaiz was also detained at a police station near his house when he defied restrictions and attempted to march towards Anantnag.