A petrol bomb was hurled at the RSS office in Mattannur, Kannur during the protest against the arrest of the Popular Front of India's state leaders.
A two-member group reached on a scooter, threw the petrol bomb, and broke the window panes.
A day after Popular Front of India leaders was arrested in a massive country-wide raid, the outfit's dawn-to dusk hartal began on Friday and incidents of stone pelting and attack on vehicles including KSRTC buses by protesters were reported from various places in the state.
The shutdown in Kerala has been called by the PFI to protest against the arrest of its members in nationwide raids by the National Investigation Agency yesterday.
The hartal (strike) started at 6 am and will continue for 12 hours till 6 pm, informed a protester.
In various other parts of the state, the roads were seen deserted this morning with few people on the roads.
According to the police, stone-pelting incidents were reported at various places in the state.
Two police officers were attacked earlier today by the hartal supporters at Pallimukku in the Kollam district.
Visuals showed hartal supporters pelting stones at the Kerala State Transport Corporation (KSRTC) bus at Panamaram village in Wayanad district. The bus was going to Kozhikode.KSRTC buses were also attacked in Kozhikode, Kochi, Alappuzha and Kollam.
In the state capital of Thiruvananthapuram, an autorickshaw and a car were seen in a damaged state after being attacked in Poonthura.
Releasing a statement, the PFI state committee said that it considered the NIA's arrest of PFI national and state leaders "unjust" and "part of atrocities by the state".
"A hartal will be held in the state on September 23, Friday) against the RSS-controlled fascist government's move to use central agencies to silence dissenting voices," it said.
The PFI also called upon the "democratic believers" to make success the strike against the "fascist regime that crush the civil rights".
According to the police, stone-pelting incidents are being reported at various places in the state.Two miscreants on a bike at Pallimukku in the Kollam district abused police officials and hit them after they attempted to stop them, police said.
The injured police officials identified as Antony and Nikhil have been admitted to the hospital. The police said the bike number of the assailants has been noted and they will soon be taken into custody.
In Kottayam, roads were seen deserted.
Earlier on Thursday, the PFI, while condemning the raids by the NIA and the Enforcement Directorate (ED) against its leaders, stated that it will "never surrender" and alleged that the agency's claims are aimed at "creating an atmosphere of terror".
A total of 106 Popular Front of India (PFI) cadres were arrested yesterday in a joint operation conducted by the National Investigation Agency, Enforcement Directorate and state police forces across 15 states in the country's multiple locations, according to the sources.
The states where the raids were conducted included Andhra Pradesh (4 places), Telangana (1), Delhi (19), Kerala (11), Karnataka (8), Tamil Nadu (3), Uttar Pradesh (1), Rajasthan (2), Hyderabad (5), Assam, Madhya Pradesh, Maharashtra, Goa, West Bengal, Bihar and Manipur.
The searches were conducted in connection with five cases registered by the NIA following "continued inputs and evidence" that the PFI leaders and cadres were involved in the funding of terrorism and terrorist activities, organising training camps for providing armed training and radicalising people to join banned organisations.
A large number of criminal cases have been registered in different states over the last few years against the PFI and its leaders and members for their involvement in many violent acts.Earlier on Thursday, the PFI and SDPI workers staged a protest in Karnataka's Mangaluru against the raids, following which they were detained by the state police.
PFI workers sat on the road in protest against the NIA raid at the party office in Chennai.The PFI was launched in Kerala in 2006. (ANI)