The police said that the killed activist, E Manoj, was a district level office-bearer of the RSS.
The day-long hartal called by RSS in Kerala today to protest murder of an activist in Kannur district disrupted normal life across the state.
Initial reports said buses, taxis and autorickshaws kept off the roads and shops remained closed all over the state.
The state government has declared a holiday for educational institutions, including professional colleges and universities postponed examinations scheduled for the day.
Barring stray incidents of stone-pelting at buses no major violence had been reported from anywhere, police said.
Manoj (42), a district office-bearer of RSS was hacked to death by a gang that attacked him in politically-volatile Kathirur in Kannur district in north Kerala on Monday. Two others were injured, one of them seriously, in the attack.
Country-made bombs were hurled at the car in which Manoj and his companions were travelling and the attackers then hacked him to death.
RSS-BJP leaders alleged that the CPI(M) was behind the killing and gave a call for a dawn-to-dusk hartal in the state for today.
Four persons, stated to be CPI(M) workers, have been taken into custody for questioning in connection with the incident, police said.
BJP President Amit Shah, who was in the state on Monday, condemned the killing at a convention of party workers. The party has pledged support to the hartal.
The area, which was witness to violence involving RSS and CPI(M) workers in the past, had remained largely calm in the last few years.
But tension resurfaced with BJP and CPI(M) poaching workers from each side in recent times.
A report from Kozhikode said the hartal was near total with all forms of transport, including private buses, taxis, lorries and autorickshaws off the roads.
Only two-wheelers and some private cars were seen plying in the town. Inter-state bus transport was also affected, it said.
Police said they have intensified the search for the culprits involved in the murder and that some people had been taken into custody to interrogation.
In Kasargod district, Kasargod taluk and Manjeshwar taluk were exempted from the hartal in view of the Ganesha festival.