Government forces launched Cordon and Search Operation in Lal Chowk area of Srinagar on Saturday.
An eye witness said that a large contingent of forces including Police and CRPF personnel arrived in the city center and erected barricades.
He said commuters are being frisked and buildings around the clock tower are also being checked.
“Drones have been pressed into services as well to survey the area,” he added.
The CASO comes a day after suspected militants lobbed a grenade on CRPF party near Ganta Ghar.
When last reports came in CASO was underway in the area.