Singh said the use of armed drones by Pakistan-based terrorists is a “very serious threat” to the security system and there was a need to have a relook at the security of vital places and persons.

"We have got very serious and strong suspicion that LeT is involved in this case.... Since LeT is involved and the outfit is run from Pakistan, so in a way Pakistan''s involvement cannot be ruled out," the police chief told reporters on the sidelines of a function in Kathua district.

To what extent Pakistani agencies are involved would be known only when the investigation proceeds further, he added.

The National Investigation Agency (NIA) has taken over the investigation into the first-of-its-kind drone attack on the Indian Air Force (IAF) station at Jammu airport on June 27.

Two bombs were dropped from drones, causing minor injuries to two airmen. The first blast ripped off the roof of a single-storey building at the technical area of the Jammu airport manned by the IAF. The second one was on the ground. A cocktail of explosive material, including RDX, is believed to have been used.

Referring to the seizure of a 5.5-kg improvised explosive device (IED) in Jammu hours after the twin blasts at the IAF station, Singh said, "They were planning to trigger an explosion at a crowded place with the aim to cause the largest possible casualties. But luckily we were able to intercept and capture the fellow (terrorist) who gave certain leads and we were able to recover the IED and avert a major terror attack."

The Director General of Police (DGP) said over a dozen incidents had taken place earlier wherein the LeT was involved in dropping weapons, ready-made IEDs and narcotics using drones.

Asked whether the recovery of the IED and the IAF bombing are linked, he said, “I would not be able to say at this point of time that the two are connected. But we are trying to prove if there is any linkage.”The DGP said it is very much possible that the drones came from across the border.

"In the earlier drone droppings, the drones covered a distance of 10 to 15 km and the aerial distance of the Jammu airport (from the international border) is not more than that. The particular route which is suspected to have been taken by the drone if it had come from across also comes within the range of 15 km,” he said.

Singh said there have been incidents of drone droppings in Akhnoor and Arnia on the outskirts of Jammu and Samba and the initial indications and questioning of people who have been caught pointed towards it.

"It is very much possible that it (drone) has come from across but other angles would also not be ruled out at this stage,” he said.

In response to a question about the threat posed by the use of armed drones, Singh said it is a very serious threat to the security system.

“Under the international protocol, this kind of activity is not supposed to be taking place but if it has started and some terrorist outfits are involved in this, it poses a serious threat. We have a relook of the security of the vital places and important persons. The threat does not respect the parameters of the security,” he said.