Several antiques were stolen from the imperial tomb of King Khai Dinh (1885-1925) in the central city of Hue on Wednesday.
The theft was detected at 2.30 a.m. by security guards and a police investigation is currently underway, said Phung Phu, Director of the center for Hue Ancient City's Relics Preservation.
Phu declined to elaborate on the crime until police reach a conclusion.
However, a source told Tuoi Tre that at least seven silver exhibits, which belonged to the collection of items used by the penultimate king of Vietnam's Nguyen Dynasty (1802-1945), were stolen.
Previously, thieves have broken into the royal tombs of Tu Duc and Dong Khanh, another two kings of the Nguyen Dynasty, in 2008 and 2009, but they were accosted by security guards and managed to flee the scenes, according to the source.