Senior Congress leader Digvijaya Singh left Kerala for Delhi and is likely to file his nomination for the election to the party president's post.
Singh was participating in the party's Bharat Jodo Yatra which was currently in Kerala.
Nominations for the Congress president's election can be filed till September 30.
The former Madhya Pradesh chief minister is the latest entrant in the fray for the party chief's election, even as the fate of Rajasthan Chief Minister Ashok Gehlot contesting the party chief's election is uncertain.