Amid heavy security at key locations in the city, Dal Khalsa activists today launched a campaign to garner support for its shutdown call for June 6 to mark the Operation Bluestar anniversary.To deal with any untoward incident, paramilitary forces, and police commandoes have been deputed at key locations, especially around the Golden Temple complex, said Police Commissioner Amar Singh Chahal. The paramilitary forces today conducted a flag march in city.As a preventive measure, the police have started arresting radical leaders. Sikh Youth Federation (Bhindrawale) president Gurjinder Singh, who recently announced to disrupt the customary address of Akal Takht Jathedar Giani Gurbachan Singh, was detained today, said SSP (Tarn Taran) Manmohan Kumar Sharma.Sources said more arrests were likely to be made ahead of the Operation Bluestar anniversary.Several Sikh organisations have supported the bandh call. Dal Khalsa spokesperson Kanwar Pal Singh said medical stores would be allowed to remain open. He said the bandh would be peaceful and road and rail traffic would not be disrupted.