The chief minister was in the city to address a public meeting to mark the occasion of BJP's three years in the state.
"The congress members, led by Bikaner Congress president Yashpal Gehlot, were carrying black ribbons in their pockets at Gajner road and were planning to show to the chief minister when there cavalcade was about to pass from there," Sadar police station SHO Laxman Singh said.
All of them were detained before they could wave the ribbons, he said.