The incident occurred at Kallachi around 8:30 pm. The injured have been identified as Babu, Vineesh, Sudhir and Sunil, officials added.
While Babu and Vineesh, who suffered severe injuries in the abdomen and legs, have been admitted to the Kozhikode Medical College Hospital (KMCH), the other two have been taken to a private hospital in Kozhikode, a senior police official said.
"Investigation is underway to ascertain the motive behind the attack", the official said. The attack took place hours after an RSS functionary in Madhya Pradesh announced Rs one crore bounty for beheading Kerala Chief Minister Pinarayi Vijayan.
Kundan Chandravat, 'Sah Prachar Pramukh' of RSS in Madhya Pradesh's Ujjain, announced the reward to avenge the killing of its workers in Kerala, allegedly by CPI-M workers.
"The Kerala Chief Minister is killing our RSS workers who want to take this country forward. I will pay Rs one crore to anyone who beheads him even if I have to sell my house," Chandravat was seen saying in a video, which went viral. The RSS, however, distanced itself from Chandravat's remarks.