A large-scale construction project is underway for the establishment of an evacuation shelter in Seoul's Gangnam district amid growing interest for such facilities following the warning alarm sent out earlier in the week, according to industry sources Tuesday.

According to Hyundai Engineering & Construction, a South Korean builder in charge of reconstructing Banpo Jugong apartment complex 1 in Seocho-gu, southern Seoul, an extensive underground evacuation shelter is planned to be constructed under the reconstructed complex.

Since winning a bid for the reconstruction project in 2017, Hyundai E&C has announced that it would build a luxury apartment complex called The H Claest.

The project -- considered the largest-scale such project in Gangnam worth some 10 trillion won ($7.7 billion) -- will take place on 248,611 square meters of land and involve the construction of 55 buildings that will house a total of 5,002 households.

According to Hyundai E&C's bid proposal for The H Claest, the evacuation shelter will be built under the roadway currently located between the first and second districts of Banpo Jugong apartment complex 1.

The shelter will consist of concrete walls more than 1.1 meters thick, along with accommodations such as toilets and shower facilities for men and women. In addition, a storage room for daily necessities will be included to prepare for a long-term war.

A Hyundai E&C official told The Korea Herald's sister paper Herald Business that in case of chemical warfare or a nuclear attack, the builder is planning to install devices in the shelter to block outside air from seeping in.