(CNN) — The construction of what would be Seoul’s tallest building has hit a snag following the appearance of a number of mysterious sinkholes in and around the neighborhood where it is being built.

Residents of South Korea’s capital are alarmed by the increasing incidence of sinkholes — depressions, measuring up to several feet in depth and diameter, which have suddenly appeared around Seoul.

The first one was discovered in June, and since then several others have appeared, local media have reported. Now, in a climate marked by increased safety concerns, the construction of a huge skyscraper in the city has come under scrutiny.

Last month, two holes within a couple of meters of each other were discovered near the National Assembly in the Yeouido district of the capital. Read More.