The reason for the attack is under investigation, police said.
Two Dalit men were hacked to death and another seriously injured by a six-member armed gang in Tirunelveli on Monday night, police said.
The gang followed the three men, who were travelling on a two-wheeler, waylaid and attacked them near a petrol station on the Tenkasi road.
Police said Shanmugam (54) and Mariappan (33) died on the spot, while Rajkumar was seriously injured and admitted to hospital.
The reason for the attack is under investigation, police said.
Tension prevailed at Paraiyadi where the deceased lived and armed policemen have been posted in the area.
Special teams have been formed to nab the culprits, police added.