Defence Minister Manohar Parrikar has sought a report from the Indian Air Force (IAF) on how militants managed to enter the high-security airbase.

Initial analysis of events at the IAF headquarters point the fingers towards a water canal, which breached the 23-km long perimeter wall of the front line airbase that witnessed action in 1971 war with Pakistan.

The air station currently houses MiG-21 fighter jets besides Mi-25 and Mi-35 helicopter gunships. Close to 1500 people live inside the air station, which also has a terminal for civilian flights. The base has five entry gates, four of which remained closed. The fifth one is the main gate.

 It is located in the more populated civilian side of the air station.

IAF officials say terrorists did not enter from that side; otherwise the casualty would have been much more.

This narrows down the suspected entry point, somewhere close to the canal, which ran parallel to the boundary wall before taking a turn to enter the premise.

 Once the operations are over, IAF will check if the ultras used the canal as their entry point or sneaked through a hole in the wall.

Another theory that terrorists may have entered the base even before the alert was sounded would also be examined critically once the operations are over.

Agencies suspect there were at least six terrorists and they were divided into two groups – one of four and the other with minimum two.

The first group were killed on Saturday while the members of the second group fought for almost 60 hours.

The security of military installations is also set to be reviewed besides a relook at the training of the Defence Security Corps personnel and military police personnel.