TNA members and supporters of MP Mahendralingam, were attacked by members of Pillayan's TMVP group on Wednesday morning, reported Uthayan.
The TNA supporters were gathered at an election campaign event in Selvanakar, Batticoloa district, ready for the Eastern Provincial council elections in September.
Last month, TMVP threatened residents Vaakarai and warned them against voting for the TNA in the elections.
The attack was allegedly carried out by supporters of TMVP member Prasanthan, who initially began a verbal argument before physically attacking the TNA members.