The authorities in India's eastern city of Calcutta have increased surveillance operations on the city's underground railway stations.
At least 60 more cameras have been installed, officials say.
The Chief Security Commissioner of the Calcutta Metro, SG Samuel told journalists the cameras would monitor movement of the passengers.
The move follows the attacks on London's underground in July this year, Mr Samuel said.
The BBC's Subir Bhaumik in Calcutta says the cameras have been installed at the entry and exit points of all of the city's 15 metro stations as a security measure.
There are more than 250 cameras already installed in the stations.
Security has already been tightened in the underground stations in India's capital Delhi.