At least seven people, including a police officer, have been injured in a collision on a motorway near Tuen Mun.
Police said the incident happened at around 5pm on Friday on Kong Sham Western Highway.
A Citybus is believed to have hit a police vehicle that had stopped along the road to handle a traffic incident.
A taxi was also hit.
A police officer was hurt after he reportedly jumped off the expressway to avoid being hit.
Police Commissioner Joe Chow arrived at Tuen Mun Hospital to visit to the injured officer.
The bus driver was arrested on suspicion of dangerous driving causing grievous bodily harm.
The Transport Department said part of the northbound lanes of Kong Sham Western Highway near Ha Tsuen was closed because of the crash.
