The Congress continued its protest for the fourth day on Friday over the suspension of 25 MPs by Lok Sabha Speaker Sumitra Mahajan.
Party president Sonia Gandhi and vice president Rahul Gandhi led the protest near Mahatma Gandhi's statue in the parliament complex.
The protestors wore black bands on their arms.
On Monday, Mahajan had suspended the Congress MPs for five days for "wilfully obstructing the business of the house" and not adhering to her repeated requests to observe the rules of the house.