Authorities have beefed up security in Kolkata in the wake of the 12-hour 'Bangla Bandh' called by the Bharatiya Janata Party (BJP) in protest against the alleged police crackdown during the 'Nabanna Abhijan' protest rally in the state capital on Tuesday, reported news agency ANI.

The murder and alleged sexual assault of a female trainee doctor at RG Kar Medical College and Hospital on August 9 caused national outrage and many rallies have been held in different states of the country.