A Congress ticket aspirant was injured after he was attacked by supporters of another hopeful outside the venue of the Congress screening committee meeting in Assam on Sunday, sources said.
A woman leader of the party also suffered injuries in the incident, they said.
The high-level meeting is underway at a luxury resort on the outskirts of Guwahati to decide the second list of Congress candidates for the Assam Assembly polls.
Hundreds of supporters of two Congress aspirants from Kamalpur constituency gathered at the venue in the morning after news spread that AGP MLA Satyabrat Kalita from the same seat is likely to join Congress and get a ticket from there.
The AGP has surrendered the Kamalpur seat to its partner BJP, which has fielded Diganta Kalita for the election.
Congress supporters of Harish Patowary and Kishore Bhatta opposed the idea of giving tickets to Satyabrat Kalita.
Amid sloganeering, Mr Patowary received blows on his face from supporters of Mr Bhatta when he was about to get inside the venue, the sources said.
Another woman leader from the Kamalpur constituency suffered injuries on her hand during the fight.
The security officers of Congress leaders then controlled the crowd and later, the local police reached the spot.
Congress MP Gaurav Gogoi also came out of the meeting and asked the crowd to disperse or face strict disciplinary action.
The opposition party had late on Saturday issued a list of 40 candidates for the first phase of polling, for which the last date of nomination is Tuesday.
The party has not yet shared the seat-sharing arrangements with its partners in the Grand Alliance.
Besides the Congress, the other members of the alliance are the AGM, AIUDF, BPF, CPI(M), CPI and CPI(ML).
Elections to the 126-member Assam assembly will be held in three phases on March 27, April 1 and April 6.