Photo: CCTV Asia Pacific 

BEIJING, Jan. 22 (Xinhua) -- A spokesperson for the Hong Kong and Macao Affairs Office of China's State Council Wednesday expressed condolences over the death of three on-duty customs officers in Hong Kong.

Xu Luying also extended sincere sympathies to the families of the deceased as well as the injured personnel.

A patrol vessel of the Hong Kong Customs sank while on duty in the waters near Sha Chau around 9 p.m. Tuesday, Xu said. 

Three customs officers died in the accident, while the other two on the vessel were injured, Xu said.

The cause of the accident is still under investigation.