The car of BJP Tamil Nadu unit General Secretary A Ramesh was partially damaged when a petrol bomb was thrown on it allegedly by activists of Periyar Dravidar Kazhagam in the wee hours of on Thursday in Salem.
The bomb was hurled at the car which was parked at the residence of Ramesh, police said.
City Police Commissioner N Vanniyaperumal said a case had been registered against six PDK workers, including one woman, for various offences, including violation of prohibitory orders and possession of firm arms.
However, no arrests had been made.
The attack is seen as a retaliation to the burning down of a two-wheeler belonging to a PDK volunteer last week allegedly by BJP workers following a protest by the organisation against the conduct of the party's state executive meet in the city.
Ramesh told PTI that he received an anymous phone call around 3 am stating that a petrol bomb would be thrown on his house.
Around 4 am, five persons came in three motorcycles and threw the petrol bomb on the parked car and escaped under the cover of darkness, he said.
BJP workers later held a demonstration in front of the police commissionerate condemning the attack and 'inaction' by the police to arrest the culprits.