The Central Industrial Security Force has installed X-ray scanners at the entrances of eight airports ' in Delhi, Mumbai, Hyderabad, Bangalore, Chennai, Guwahati, Kochi and Bhopal ' to put people identified through "profiling" through an additional round of security check, a senior official said.

"Not all passengers are asked to put their bags through these scanners, only those selected through profiling. We want to ensure no kind of firearm or weapon enters the building before the passenger goes through any kind of security check beyond the check-in counter," said SDG, Airports, R R Verma. "The area between the entry gates and the check-in counters is the most vulnerable. If nothing else, there can be a shooting incident in this area and there could be a good number of casualties also."

The focus of the exercise, a senior official said, is on anti-hijack preparedness and detection of explosives.

Since the introduction of in-line baggage handling at all busy airports in India, a passenger goes through the first security check after crossing check-in counters. This system is equipped to scrutinise the checked-in baggage but not the hand baggage, which is checked after the passenger has got her boarding pass, the official said.

"To fix this gap, we started this exercise on an experimental basis and now we will extend it to non-metro airports as well. The security personnel at the entrance only asks for the ticket and ID card of a passenger, so it is easy for anybody to sneak in a weapon," the official added.