A Communist Party of India (Marxist) (CPI-M) worker was attacked in Kannur on 28 December morning.
The party has alleged that Rashtriya Swayamsevak Sangh (RSS) is behind the attack.
The worker, identified as Chandran, suffered injuries on his legs and was immediately admitted to a nearby hospital for treatment.
A CPI-M worker was also left injured yesterday by a group of unidentified men in Kerala's Thiruvananthapuram. The attackers are yet to be identified.
Earlier on November 19, another CPI-M worker was injured after a crude bomb was hurled at a rally.
The incident had happened a day after Mayor V. K. Prasant was attacked by the Bharatiya Janata Party (BJP) workers at the city corporation council.
CPI-M District Secretary Anavoor Nagappan alleged that the BJP workers had unleashed violence on the workers of his party during a procession.
However, in October, an RSS activist was injured, while bombs were hurled at a BJP party office.
Both left and the right-wing outfits in Kerala are accusing each other of the increased hostilities as the incidents of political violence are rising in the state. Kerala has a long history of political violence.
Police records of political murders between 2000 and 2017 question both the left and right-wing fronts.
In the last 17 years, 85 CPM workers, 65 RSS or BJP workers, 11 workers of Congress and IUML each have been killed.