A crude bomb was thrown at a retail chain store in Chennai, founder-chairman of which is Andhra Pradesh Chief Minister N Chandrababu Naidu.
No one was injured in the incident which happened late on Sunday night, police said.
Four activists of a pro-Tamil outfit were on Monday taken into custody for questioning in connection with the attack.
Twenty people from Tamil Nadu were gunned down in a police operation in Seshachalam hill ranges of Chittoor district in Andhra Pradesh on April 7.
Naidu has come under attack from various groups in Tamil Nadu for the incident and his effigies have also been burnt in recent days in some parts of the state in this regard.