"The security grid is in place and you are probably listening to some surveillance operation which is going on at top (helicopters)," General Officer Commanding of the Army's 15 Corps Lt General Subrata Saha told media persons in Srinagar.
Several helicopters could be seen flying over the cricket stadium where Modi will address his first election rally in Kashmir on Monday.
"So the grid is very much in place and it is highly effective. I do not think it will be appropriate for me to reveal anything more than that," Lt Gen Saha said.
The security forces -- including police and paramilitary CRPF -- have been deployed in strength across the Srinagar city while all roads leading to the venue of the rally have been sealed.
Concertina wires have been laid at several intersections in city's Dalgate, Sonawar, Gupkar Road and TRC Crossing to block the movement of vehicles and people towards the stadium.
A posse of policemen and CRPF personnel have been deployed at each intersection to ensure that the security drill is followed in letter and spirit, a senior police officer said.
In other parts of the city, motor vehicle checking points have been established by security forces for checking the vehicles moving around. The intelligence agencies and police have been directed to keep an eye on the suspected persons, the officer said.
Barricades have also been set up at the entry points to the city to ensure that terrorists are not able to sneak in to carry out any act of sabotage, he added.
Security personnel have taken positions at vantage points on the buildings around the venue of the Prime Minister's rally as part of area domination exercise.
The security drill, meanwhile, has resulted in massive traffic jams with vehicles, coming from other districts, diverted through the city.
The traffic near TRC Crossing and Badyari Chowk in Dalgate was moving at a snail's pace due to the restrictions imposed on movement around the venue of the rally.
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