Seven pieces of art have been stolen from the Palace Museum inside the Forbidden City in Beijing.
It is the first theft from the former imperial palace, for 20 years.
The stolen items were on loan from Liangyicang, a private collection in Hong Kong.
The BBC reports they date from the beginning of the last century. Some are encrusted with precious stones.
The Beijing News reported that the Hong Kong museum had not insured the items for as much as it could have because it believed they would be safe in Beijing.
The Palace Museum is based within the Forbidden City, home to the emperors during the Ming and Qing dynasties.
The complex comprises courtyards, palaces and gardens. It became a museum in 1921 after the fall of the last Emperor Puyi a decade earlier.
The thief got into the complex by knocking a hole in a wall. Police are reported to be looking for a 27-year-old man.
