Police officers on the Delhi Police's behalf used batons and lathi to tear Priyanka Gandhi Vadra from the protest route, leaving her on the ground.
The attack came as a group of Congress MPs were attempting to march to the Election Commission's office, protesting alleged irregularities in the Special Intensive Revision exercise.
Rahul Gandhi and other opposition MPs were detained, sparking condemnation from the Congress leadership.
Congress MP Charanjit Singh Channi called the centre's actions 'hooliganism', while Pawan Khera accused Delhi Police of intimidation.
The incident follows a previous protest at Akashvani Bhawan, where opposition leaders staged a dharna.
A joint opposition statement demands an independent inquiry and a review of policing protocols at parliamentary protest sites, with a parliamentary committee set to convene next week.