The massacre of nine civilians by Sri Lankan police at the fourth World Tamil Research Conference in 1974 was remembered in Jaffna on Sunday.
Three students, a teacher and a doctor were among those killed.
Residents and politicians took part in the event, including the head of the Ilankai Thamizh Arasu Katchi (ITAK), Mavai Senathirajah, and the Northern Provincial Council members C V K Sivagnanam, M K Shivajilingham and P Kajatheepan.