Congress workers and leaders gathered at the party headquarters on Tuesday to show solidarity as Sonia Gandhi appeared before the ED in the National Herald case for a second time in 5 days.
Earlier, Congress leader Ajay Maken said that the party would stage a satyagraha across the country.
"We decided that we will conduct satyagraha at Raj Ghat inside Delhi and our satyagraha will continue till Sonia Gandhi ji is not allowed to go back after interrogation," Maken said in a briefing.
Maken also said, "We want to tell the BJP government that democracy has two wheels, a ruling party and an opposition. If a single wheel slips, the car of democracy will stop there, so let the wheel of the opposition do the work.
All India Mahila Congress also protested near the party headquarters against the government's use of probe agencies for opposition leaders. Congress' interim president Sonia Gandhi will appear before ED today for the second round of questioning in connection with the National Herald case.
Media reports showed barricades outside the AICC office where Congress workers gathered.
Meanwhile paramilitary forces have been deployed in and around the probe agency's headquarters, as well as additional police teams.
The police is also checking every vehicle and inquiring everyone heading towards the APJ Abdul Kalam Road.
The Delhi Traffic Police has said that due to special arrangements, there will be heavy traffic movement till 2 p.m. on Gol Methi junction, Tughlak Road Junction, Claridges Junction, Q-point Junction, Sunehri Masjid Junction, Maulana Azad Road Junction and Man Singh Road Junction.
On July 21, Sonia Gandhi was questioned for hours by the ED.
She was initially summoned to appear again on July 25 but it was changed to July 26 at her request.
On Tuesday, the Congress President will be questioned by a team led by Additional Director Monika Sharma.
On July 21, she was accompanied by her son Rahul Gandhi and daughter Priyanka Gandhi Vadra.
(With agency inputs)