A youth movement that started as an online joke is now at the center of a major fight in India. The Cockroach Janta Party says police have detained at least 10,000 people nationwide before a protest it plans to hold Saturday at Jantar Mantar, the official protest site in New Delhi, The Guardian reported.

The protesters want Chief Election Commissioner Gyanesh Kumar to quit over a review of voter lists. More than 130 million names have been cut so far, and millions of people have appealed. The opposition says the cuts hit its own voters hardest, while the Election Commission and the government say the review only removes duplicate and ineligible entries.

The party says students, farmers and members of Dalit groups were among those held. About 22 women students traveling from Pune to Delhi were held by police in Madhya Pradesh and taken to a hotel, Scroll reported, citing The Hindu. The party also said one of its leaders, Deepak Baliyan, was taken from his home in Rajasthan. It later said he was let go late at night, Business Standard reported.

Delhi police have refused to allow Saturday's protest and banned gatherings near Parliament. About 23,000 security personnel are expected to be deployed across the city, Scroll reported, citing the ANI news agency. The Delhi government also ordered liquor shops closed on Friday and Saturday.

The party's founder, Abhijeet Dipke, said the march will go ahead anyway.

The movement began online in May and has grown fast. Earlier protests it led over leaked exam papers helped force the resignation of Prime Minister Narendra Modi's education minister, The Guardian reported.

Opposition leaders are also pressing the issue. Police briefly detained Congress leader Rahul Gandhi and his sister Priyanka on Wednesday as they tried to reach the protest site. The opposition INDIA bloc meets Friday to plan its next steps and is seeking a meeting with President Droupadi Murmu.

What we know: Delhi police have refused permission for Saturday's march, and the party says thousands have been detained.
What we don't: How many people will reach the protest, and how police will respond.