President Donald J. Trump said the U.S. military is constructing a large complex beneath a new White House ballroom project.

He described the underground facility as including advanced security features such as bulletproof glass and drone-resistant structures.

Trump claimed the military had wanted the addition and that its details were originally meant to remain secret.

The ballroom, reportedly funded by private donations, is planned for events like state dinners and international gatherings, The Hill has reported.

The construction has drawn controversy due to the demolition of part of the East Wing and concerns about transparency and cost.