Rahul Gandhi and his sister, Congress MP Priyanka Gandhi Vadra, were among the leaders taken into custody around 8 pm.

Visuals showed police personnel dragging Rahul Gandhi away as Congress workers attempted to resist the detention.

Congress sources said the detained leaders were being taken to Kingsway Camp in north Delhi.

'EC office is barely 50 metres away': Rahul Gandhi

The protest was organised by the INDIA bloc against what the Opposition has described as "unilateral" decisions by Chief Election Commissioner Gyanesh Kumar and alleged irregularities in the Special Intensive Revision (SIR) of electoral rolls.

Earlier in the day, Gandhi questioned why Opposition MPs were being prevented from meeting the Election Commission.

"The Election Commission office is barely 50 metres away, but we were not allowed to go there. I do not understand what the problem is," Gandhi said.

He claimed that around 300 MPs wanted to meet Gyanesh Kumar and accused the Chief Election Commissioner of being "scared".

"If the representatives of the people cannot meet the Election Commission, then what is the meaning of democracy?" he asked.

Gandhi siblings detained twice in a day

Tuesday's evening detention was not the first time Rahul and Priyanka Gandhi were taken into custody.

The siblings were briefly made to board a police bus around noon before being released later.

The evening detention came after the Opposition MPs continued their sit-in near the Election Commission headquarters.

Congress sources said the party had also written to the Chief Election Commissioner and the two Election Commissioners seeking an appointment.

Congress plans campaign till winter session

The Congress has drawn up an extended protest programme to keep the Election Commission and SIR issue in the political spotlight.

From October 10 to 20, the party plans to hold a "Save Vote, Save Country" campaign at the block level, including bicycle and motorcycle rallies, distribution of leaflets and protests targeting Gyanesh Kumar.

Booth-level public meetings, or chaupals, are planned from October 25 to November 25, with senior Congress leaders expected to participate.

The party has also announced a major rally at Delhi's Ramlila Maidan on November 1.

On November 25 and 26, six separate "Chalo Delhi" marches are scheduled to begin from different areas around the national capital before converging in Delhi on Constitution Day, November 26.

Opposition eyes winter session, impeachment motion

The Congress is expected to take the issue into Parliament when the winter session begins after November 26.

The party has indicated that it could move an impeachment motion against Chief Election Commissioner Gyanesh Kumar.

The Opposition is also watching proceedings in the Supreme Court, where Chief Justice of India Surya Kant is hearing a case involving the Election Commission.

The court has issued notices to Gyanesh Kumar and the ECI. It has observed that where election-related decisions are not unanimous, they could potentially be stayed.

However, the Supreme Court has so far declined to take immediate action against the Chief Election Commissioner, cautioning that newspaper reports may not always provide a completely accurate account. The matter remains under consideration.