The CPI(M) area committee office at Ottappalam was attacked by two unidentified persons on Thursday night. The window panes of the office were destroyed in the attack.
Police said two persons who came on a bike hurled stones at the office around 12.30 a.m. The stones were recovered from inside the office.
CPI(M) area secretary S. Krishnadas alleged that the Congress was behind the attack.
Both the CPI(M) and the Congress had a showdown in Ottappalam town in the last three days. Both accused each other of destroying flags, posters and other properties. Police said they were investigating.