Kolkata, April 13: Amid the spurt in COVID-19 cases, police here have deployed drones, as a key surveillance instrument, to keep a tab on people's movement and prevent mass gatherings, if any, a senior officer said.

The unmanned aerial vehicles have been pressed into service over densely-populated localities -- Hatibagan and Shyambazar in northern part of the city and Burrabazar and New Market in central Kolkata - to record videos and aid the police in their efforts to enforce the lockdown order. Kerala Police Share Footage of COVID-19 Lockdown Violators Shot on Spy Drone With ‘Tracer Bullet’ Challenge Commentaries, Watch Hilarious Video.

"At the moment, three drones are being used for the purpose. We are keeping a check on crowded areas, mostly markets places, where people gather violating the lockdown rules," the senior Kolkata Police officer said. More such drones will be employed for the purpose over the next few days, he said.

"People have to understand why gatherings have been barred for now. Until then, it will be difficult to fight this virus. The metropolis is densely populated and we have to make sure everyone maintains social distancing norms," he noted.

No one will be allowed to step out of homes without wearing masks, and strict measures would be taken against those flouting the rules, the officer stated.

"Once we receive the footage from the drones, we send local police station officers there to ensure people abide by the orders. Going by the government's directive, we will not allow anyone to come out of homes without masks," he added.

The state government on Sunday made masks mandatory for people visiting public places. Meanwhile, police here have also started providing on-call taxi services for emergencies.

"This is a taxi service available only for emergencies. Not more than three persons can travel at a time. Also, anybody wanting to avail the taxi service can dial 1073, but he or she will also have to furnish relevant documents," another police officer said.

So far, West Bengal has reported 122 COVID-19 cases, according to the state health department. Of them, seven have died and 22 recovered from the disease.