A crude bomb was hurled at the BJP office near Kunnukuzhi in Thiruvananthapuram, but there was no casualty, police said on Wednesday.
The incident occurred at around midnight.
Glass panes of the main entrance door were damaged in the incident, Thiruvananthapuram city police commissioner, S Sparjan Kumar told PTI.
There were 3 to 4 BJP workers on the top floor of the office when the crude bomb was hurled, but none were injured.
BJP sources said the crude bomb exploded hardly 45 minutes after state President Kummanam Rajasekharan left the office.
To protest over the incident, BJP is taking out a march to the Secretariat here at 10 am, the sources said.
The incident occurred at the new office of the party