Political violence increased in Kannur since the run-up to the state election in May.
In Kannur, a 30-year-old BJP worker, Sugesh, was attacked with sharp weapons by a mob of men and hospitalised with a head injury. Two others have been injured in the clash.
Police sources say the attackers have not been identified but the BJP has alleged that they were CPM workers.
Despite the festivity of Krishna Jayanti, Kannur has been under tight security after a CPM worker was attacked on Wednesday by a mob of around 10 people. The CPM has held BJP responsible for the attack. The CPM worker has been admitted in a critical condition in the ICU.
Police sources told NDTV that they suspect the attack on the BJP worker is a politically retaliatory move.
Kannur in northern Kerala -- the hometown of Chief Minister Pinarayi Vijayan -- has been known for its bloody past of political murders and the rivalry between the CPM and the BJP. Around 30 people from various political parties have been killed in Kerala between 2011 and 2016.
Since 2016 election, with the CPM heading the state government and BJP at the Centre, the political slugfest has only increased.