Bangladesh, Oct. 11 -- Over 5,000 protesters, including prominent opposition leaders Mamata Banerjee, Arvind Kejriwal, Pinarayi Vijayan, Manik Sarkar and Abhijeet Dipke, were detained on Saturday as New Delhi tightened security to prevent a demonstration demanding the resignation of Chief Election Commissioner Gyanesh Kumar over alleged irregularities in the revision of electoral rolls.

The police action triggered a fresh confrontation between opposition parties and the authorities, with protesters and political leaders challenging restrictions on movement and assembly, while Congress MP Shashi Tharoor accused the government of turning the national capital into a fortress to avoid questions about electoral integrity.

The demonstration,...