The founder of India’s youth-led online “cockroach” movement and two other leaders were released on Sunday, their lawyer said, a day after they were detained to thwart a major protest against the election commissioner.

The group said thousands of protesters were detained before Saturday’s planned demonstration in New Delhi, the culmination of weeks of opposition mobilisation following allegations of misconduct during a nationwide voter roll revision.

Abhijeet Dipke and two other Cockroach Janta Party (CJP) leaders were detained before they could disembark from their flight after arriving in the capital from Mumbai.

Ratna Singh, the CJP’s head lawyer, said in a social media post that Dipke and the others had been released by an executive magistrate’s court.

She said they had been released on the condition that they made “no breach of peace for one year”.

Dipke, wearing a white shirt, was driven away in a black vehicle soon after walking out of the court, AFP reporters saw.

Authorities mounted a sweeping security operation across the capital on Saturday, detaining thousands to prevent protesters from gathering at Delhi’s Jantar Mantar protest site, the CJP and Indian media reports said.

The protest was organised to demand the resignation of the head of the Election Commission of India (ECI) over the nationwide voter-roll revision.

Media reports said the revision resulted in more than 133 million names being removed from electoral lists.

Election authorities say the exercise was aimed at eliminating duplicate, deceased and fraudulent entries.

Critics say the process has disproportionately affected minorities, particularly Muslims, potentially benefiting Prime Minister Narendra Modi’s ruling Hindu nationalist Bharatiya Janata Party.

The ECI has rejected allegations of wrongdoing.

Saturday’s detentions triggered sharp criticism from opposition leaders, who accused Modi’s government of stifling dissent, and others.

In Geneva, the UN High Commissioner for Human Rights called for the immediate and unconditional release of all those “arbitrarily detained” in New Delhi.

Both the CJP and opposition leader Rahul Gandhi have vowed to press ahead with protests despite the crackdown.

Gandhi said his Congress party “and the youth of the country will once again take to the streets in large numbers” on Monday.

“The more Modi and his government crack down, the more the anger of Gen Z and students will grow,” he said.