Indian police detained opposition leader Rahul Gandhi and several lawmakers for the third time in two days on Wednesday as they launched an unannounced protest demanding the resignation of the election chief over a controversial revision of voter lists.

Opposition parties, their student units, and the “cockroach” youth movement have been staging almost daily demonstrations seeking Chief Election Commissioner Gyanesh Kumar’s resignation, after the Indian Express newspaper last month reported disagreements within the poll panel over updating voter lists, stoking concerns over its neutrality.

Opposition lawmakers led by Congress party leader Rahul Gandhi protested on Tuesday as well, seeking a meeting with Kumar and his deputies, before police broke up their gathering and briefly detained them.

Wednesday’s protest began after a lunch meeting of lawmakers that Congress organised at a restaurant in central Delhi, close to the Jantar Mantar site where authorities permit demonstrations.

“Yesterday … Delhi Police stopped us and said you cannot protest here … so today … we will go to the designated protest site, sit there, and tell the country that, for us, Gyanesh Kumar is not the legitimate commissioner,” Gandhi told reporters, referring to Jantar Mantar.

“The people who have done this (vote theft) are traitors … Gyanesh Kumar will have to resign,” he said, before boarding a bus that was to take the lawmakers to Jantar Mantar.

New political challenge to Modi

Lawmakers in the bus held posters against the windows that said, “no vote theft, no democracy theft”, and “election commission, not BJP commission”, referring to Prime Minister Narendra Modi’s Bharatiya Janata Party.

Hundreds of Congress members accompanied the bus on foot amid heavy deployment of police and paramilitary personnel in riot gear. Police also closed the road leading to Jantar Mantar, forcing the bus to take a detour.

Gandhi later stepped out of the bus, with a live feed on his party’s YouTube channel showing him standing at the centre of a crowd of protesters and security personnel, while his sister Priyanka Vadra and other lawmakers sprawled out on the road.

Visuals showed security personnel hauling Gandhi and Vadra into separate vehicles and taking them away.

There was no immediate comment from the police on the detentions.

The demonstrations present a new political challenge to Modi midway into his third term, just months after similar protests led by the Cockroach Janta Party (CJP) youth movement forced the resignation of his education minister over exam paper leaks.

Kumar has not commented on the voter lists issue but the election commission and BJP have denied accusations of wrongdoing.