The leader of India's "Cockroach" youth movement said a major planned protest would go ahead in New Delhi on Saturday, despite the detentions of followers he estimated to run into the thousands, calling for the resignation of the top poll official.
The dispute centres on a controversial revision of voting lists that dropped 130 million voters nationwide, spurring demands by the youth movement, opposition parties, and their student units for the official, Gyanesh Kumar, to resign.
"I'll be landing in Delhi tomorrow and will march to Jantar Mantar, come what may," Abhijeet Dipke, the founder of the Cockroach Janata Party, said on X on Friday, referring to a designated protest site in the capital.
"The youth of this country are no longer scared of you," he added in the message, addressing Prime Minister Narendra Modi.
The world's largest democracy, with at least 960 million eligible voters in 2024, India began the verification effort last year ahead of elections in the eastern state of Bihar and has now covered the majority of states.
Police in the capital said the CJP did not have permission for Saturday's protest and could face legal action if protesters violated rules.
Thousands of police and paramilitary forces, including some from sensitive areas such as Indian-administered Kashmir, were being brought in to the capital, according to a government document seen by Reuters.
The CJP said police in several states were detaining thousands of its supporters as they headed for Saturday's protest.
Reuters could not immediately verify the claims or videos posted on X.
The opposition Congress, led by Rahul Gandhi, has called for a meeting of allies from more than a dozen parties opposed to Modi and the BJP.
The opposition bloc will meet President Droupadi Murmu, a constitutional figurehead, on Friday evening.
Some long-distance trains to New Delhi on Saturday were cancelled. Authorities said police had asked for fewer metro train services, with some exits shut, citing the possibility of "unruly" mobs, according to documents seen by Reuters.
Opposition parties and critics say the latest revision, nearly two decades after the last, constitutes mass disenfranchisement to favour the BJP. They want the exercise scrapped and the old voter lists reinstated.
The election commission says the numbers represent voter entries flagged during a draft revision, in an exercise still incomplete, while those wrongly removed can enroll again.