Gandhi, 51, arrived at the ED headquarters in central Delhi around 11.35 am with his "Z+" category CRPF security escort. He was accompanied by his sister and Congress general secretary Priyanka Gandhi Vadra.
A massive contingent of police and paramilitary personnel was deployed around the federal agency's office, and prohibitory orders under section 144 of the Code of Criminal Procedure (CrPC) were in force.
Over the last two days, the Wayanad MP has spent around 21 hours at the ED's office. He has been questioned over multiple sessions, and his statement was recorded under the Prevention of Money Laundering Act.
Officials said Gandhi's questioning could not be completed on Tuesday, so he was asked to continue recording his statement on Wednesday.
The investigation is related to alleged financial irregularities in the party-promoted Young Indian that owns the National Herald newspaper, published by the Associated Journals Limited.
Congress chief Sonia Gandhi and Rahul Gandhi are among the promoters and shareholders of Young Indian.
Sonia Gandhi, currently admitted to a hospital in Delhi due to Covid-related issues, has also been summoned by the agency for questioning in the case on June 23.
On Tuesday, Gandhi joined senior party leaders at a "dharna" at the Congress headquarters, where the chief ministers of Rajasthan and Chhattisgarh, Ashok Gehlot and Bhupesh Baghel, Priyanka Gandhi Vadra and party MPs were also present.
Hundreds of Congress leaders and supporters were detained outside the party headquarters at 24 Akbar Road and around central Delhi as they tried to hold a protest against the ED action for the second day.
The Delhi Police said it detained 217 Congress workers and leaders, including 15 MPs, from the New Delhi district on Tuesday for holding protests in violation of prohibitory orders despite being denied permission. They were later released, a police official said.
The BJP hit out at the opposition party, saying it is blocking roads to show its "leaders are above the law" and termed the protests "drama".
"When lawful action is taking place in a case of corruption, Congress is doing this drama and blocking roads... it shows the party considers its leaders above the law," BJP's national spokesperson Sambit Patra said.
However, Congress accused the BJP of conspiring to defame the Gandhi family and the party by destroying their credibility through a "false" money laundering case pursued by the ED.