Senior Congress leader PC Chacko on Wednesday blamed late Delhi Chief Minister Sheila Dikshit for the downfall of the party in the region.
Speaking to ANI, Chacko said that AAP took away the entire Congress vote bank.
"The downfall of the Congress party started in 2013 when Sheila ji was the Chief Minister. The emergence of a new party Aam Aadmi Party (AAP) took away the entire Congress vote bank. We could never get it back. It still remains with the AAP," he said.
Later, Chacko tendered his resignation from the post of Delhi Congress in-charge.
On Tuesday, the ruling AAP scored a landslide victory in Delhi assembly elections for the second time in a row as it swept aside both BJP, which was again restricted to single digits and Congress which drew a blank.
AAP won 62 seats in the 70-member assembly, five seats short of its 2015 tally when it had won 67 seats. The BJP won eight seats, five more than its tally in the previous election.