A bomb was dashed at the BJP office in Thiruvananthapuram at midnight.
Reportedly no one was injured.
The CPM, which governs the state in a coalition, has disapproved the allegations that they were involved in the attack.
a senior local leader, Anavoor Nagappan said, “The CPM has no role in the attack. Allegations that the CPM is behind the attack are only for political gains”.
The bomb was thrown 45 minutes after the BJP’s Kerala chief Kummanam Rajasekharan left the office.
There were three party workers on the top floor of the office when the bomb was thrown.
The CPM and BJP have been entangled in violent rivalry for decades in Kerala, especially in Kannur district, where workers from both the parties have been hacked to death with sickles and knives.
The BJP is holding a march today to protest against the attack.