Six activists of the BJP and RSS were injured in separate attacks in Kannur district, late on Tuesday.
Praveen, a 'mandal karyavahak' of the RSS, was attacked by a group of armed assailants in Kathiroor.
The RSS worker, who sustained injuries on his head and arms, is admitted to the Kozhikode Medical College Hospital.
In another incident, in Maloor in the district, five BJP activists were attacked by a group of unidentified
men.
The injured men have been identified as Sunilkumar, Gangadharan, Anish, Rajan and Mohanan.
They are admitted to a private hospital in Thalassery. The BJP called for a hartal in the Mattannur Assembly constituency on Wednesday.
The BJP has alleged the hand of the ruling CPM in the attacks, setting the tone for another round of posturing over political violence in the district, identified with a decades-long history of clashes between the CPM and Sangh Parivar.