Hitting back at Ghulam Nabi Azad over his criticism of the party leadership, the Congress on Friday linked his resignation to the end of his Rajya Sabha tenure and alleged his betrayal reveals his true character and that his DNA has "Modi-fied".

"A man who has been treated with the greatest respect by the Congress leadership has betrayed it by his vicious personal attacks which reveals his true character. GNA's DNA has been Modi-fied," Congress general secretary in-charge communications Jairam Ramesh tweeted.

Speaking with reporters, the party's media department head Pawan Khera also lashed out at Azad and linked his resignation to end of his Rajya Sabha tenure.

"As soon your Rajya Sabha term got over, you got restless. You could not stay without a post even for a second," Khera said.

Azad on Friday resigned from all party positions, including its primary membership, ahead of organisational elections and accused the leadership of committing "fraud" on the party in the name of "sham" internal polls.

He also strongly criticised Rahul Gandhi in his resignation letter.

The senior Congress leader's exit, not entirely unexpected, comes as another serious blow to the embattled 'Grand Old Party' that has seen a series of leaders leave it.

"The Congress," Ghulam Nabi said, has lost both the will and the ability under tutelage of the coterie that runs the AICC to fight for what is right for India."

"Before starting a 'Bharat jodo yatra', the leadership should have undertaken a 'Congress jodo yatra', the veteran leader said in his letter.

Ghulam Nabi Azad, a former minister in the UPA government, had been a leading member of the G-23, or the group of 23 "dissenters", who had written to Sonia Gandhi in 2020 calling for a complete overhaul of the organization and a full-time and visible leadership.