A group of persons from nearby Othakadai were on their way to Tiruchendur to offer prayers at the temple when their car hit the median and capsized at Muthaiapuram near Tuticorin, 165 km from here, they said.
A couple, their three-year old daughter and a female relative died on the spot in the accident. Ten others who were injured were hospitalised.
In the second accident, two engineers working at a desalination plant at Mamallapuram were killed when their car hit the Median at a village near Kottampatti.