This comes a day after he filed his nomination papers for the AICC president's election.
Kharge's resignation, which the 80-year-old leader sent to Congress president Sonia Gandhi on Friday night, is in line with the party's 'One person, One post' principle that was announced at the Udaipur 'Chintan Shivir' in May.
Mallikarjun Kharge has filed nomination papers to contest the post of president of Congress party. The contest for the top party post is between him and Thiruvananthapuram MP Shashi Tharoor. Kharge, a Dalit leader from Karnataka, has emerged as the clear favourite.
Senior leaders P Chidambaram, Digvijaya Singh and Pramod Tiwari are learnt to be the front-runners to take on the mantle of Leader of Opposition in Rajya Sabha.
Kharge, Tharoor and Tripathi filed nominations on the last day of the process. The nomination of K N Tripathi, a former Jharkhand minister, has been rejected.
Kharge, flanked by top Congress leaders, had filed 14 sets of nomination papers with the proposers including Ashok Gehlot, Digvijaya Singh, A K Antony, Ambika Soni, Mukul Wasnik and members from the G-23 ginger group comprising Anand Sharma, Bhupinder Hooda, Prithviraj Chavan and Manish Tewari.
