In the wake of security breaches, Hartsfield-Jackson International Airport has begun installing concertina wire on fencing around the perimeter of the airfield.

The coiled razor wire is being added on top of the existing three rows of barbed wire on about 20 miles of perimeter security fencing that surrounds the airport.

It’s in response to recent incidents that raised security concerns at the world’s busiest airport.

In June, a man scaled a fence and ran onto an active taxiway at the Atlanta airport. Then about two weeks later, another trespasser was found walking on an access road around the airfield inside the perimeter fence at around 2 a.m.

The airport is installing the concertina wire at a rate of about 450 feet a day, said Hartsfield-Jackson interim general manager Balram Bheodari.

The work will cost a total of about $5 million, to be paid for with airport funds, according to Hartsfield-Jackson.

Still under consideration are additional measures such as covering the chain link fence with fabric to make it difficult to climb.

Bheodari said the permanent solution may also include a v-shaped structure on the concertina wire “that will make it much much much more difficult” to climb. He said it would be a military-style fence that is also used by some airports in other countries.