An RSS activist was hospitalised after he was shot at in the Garden Reach area of west Kolkata on Monday.
The youth, Bir Bahadur Singh, sustained the bullet wound in his back in Lichubagan locality under Metiabruz police station.
A profusely bleeding Singh was admitted in the state-run SSKM hospital.
He blamed the Trinamool for the attack on him.
There was tension in the area after the incident, the police said.
In trouble-torn Bhatpara of 24 Parganas North district, miscreants lobbed bombs at the house of the brother of the local Trinamool councillor.
The Trinamool accused the BJP of behind behind the incident, but the latter denied it.
One person has been arrested.
In Belgharia of the same district, a BJP worker was allegedly forcibly taken to the Triamool office, where he was beaten up and stabbed with a sharp weapon.
The BJP later laid a siege on Belgharia police station and staged a demonstration demanding the arrest of culprits.
The house of a BJP councillor was vandalised allegedly by Trianamool workers in Halishahar, while a BJP supporter was beaten up in East Burdwan district's Palitpur. The BJP leadership pointed fingers at Trinamool.
The victim was admitted to Burdwan Medical College Hospital.
The Trinamool has denied its involvement in the assault and described the incident as a fallout of the factional feud in BJP.
( With inputs from IANS )