The Congress MLAs individually submitted their preference for CLP leader to senior leaders C P Joshi and Ambika Soni at a meeting here.
Congress insiders said Mannan is ahead of Bhuniya as he is known to be an anti-TMC face in Congress and also one of the main architects of Congress-CPI(M) alliance.
"Today I have come here to meet the Congress MLAs and take their views and prepare a road map for the party in days to come," Soni told reporters.
Five other MLAs who were absent in the meeting were said to have spoken to the leadership over phone.
"After a general meeting, all MLAs are meeting Ambika Sonia and C P Joshi individually where they are being given a paper to write down the name of the person whom they want as the CLP leader. Soni and Joshi will take those papers and submit it to our party president Sonia Gandhi, who will take the final call," a senior Congress MLA told PTI.
