An FIR was registered against Dukhtaran-e-Millat chief Aasiya Andrabi for allegedly hoisting Pakistani flag on the neighbouring country's national day on Monday.
"A case has been registered against Andrabi at Nowhatta Police station under Section 13 of Unlawful Activities Prevention Act," a police officer said.
He said investigations have started into the alleged hoisting of Pakistani flag by the separatist leader, PTI reported.
"Further action in the case will be taken as per rules," the officer said when asked if the firebrand separatist leader will be arrested.
A controversy erupted following media reports claiming that the separatist leader had hoisted flag of Pakistan and sung its national anthem on March 23.