Opposition leaders and journalists accused police of heavy-handed tactics during weekend demonstrations, as authorities locked down New Delhi on Monday ahead of a fresh rally against the election chief.
Authorities deployed thousands of personnel across central Delhi for a third straight day, erecting heavy metal barricades and closing key metro stations before a march called by opposition leader Rahul Gandhi, reported AFP.
The protests were triggered by allegations of misconduct during a nationwide voter roll revision that critics say could benefit Prime Minister Narendra Modi's ruling Bharatiya Janata Party (BJP).
The Election Commission of India, which oversees the voting process in the world's most populous nation, has denied wrongdoing.
But attention has increasingly shifted to the police response after a chaotic weekend in which thousands of protesters, including members of the youth-led Cockroach Janta Party (CJP) movement, were detained, according to local media reports.
Most of those detained, including three top leaders of the CJP, have since been released.
Opposition figures have accused authorities of trying to suppress dissent through mass detentions.
Parliamentarian John Brittas of the Communist Party of India (Marxist) alleged he was "manhandled, dragged, assaulted" by police during Sunday's demonstrations.
"This is not merely an assault on an MP. It is an assault on democratic freedoms and the rule of law," Brittas said.
Police did not respond to questions on detentions or their actions during a news conference on Sunday.
Several journalists covering the protest said they were detained despite prominently displaying their press cards.
Reporters Without Borders (RSF) said at least 16 journalists were detained during the weekend protests, calling the actions "unacceptable".
- 'Nothing to fear' -
The capital was bracing for a fresh showdown on Monday, with Gandhi, leader of the Congress party, urging supporters to join a march to the Supreme Court.
"There is nothing to fear," he said on social media on Sunday. "These cowards can do absolutely nothing to us."
Hundreds of yellow metal barricades were set up on roads leading to central Delhi, while six major metro stations remained shut.
The leaders of the CJP, which has millions of social media followers, have pledged to continue their protests until Chief Election Commissioner Gyanesh Kumar steps down.
The protests have become one of the most significant political challenges of Modi's third term, drawing together opposition parties, student groups and activists angered by the voter roll revision.
The revision resulted in more than 133 million names being removed from electoral lists, according to media reports.
Critics say the measure has disproportionately affected minorities, particularly Muslims.
Election authorities say the move was intended to eliminate duplicate, deceased and fraudulent entries.
