SINGAPORE - Three vehicles, including a prison van, were involved in an accident on Friday (May 13) afternoon that injured eight.

The prison vehicle was caught between a van and a tipper truck carrying gravel, Chinese daily Lianhe Wanbao reported.

The 59-year-old tipper truck driver was arrested in relation to the case, police said.

Two of those injured were prison inmates, the Singapore Civil Defence Force (SCDF) said.

SCDF said that it was alerted to the accident on the Pan-Island Expressway near Tampines at 2.55pm.

Eight people, including two inmates, were taken to the Changi General Hospital. It is understood that their injuries were light.

The door of one of the vehicles was jammed, and opened by the SCDF using using hydraulic rescue tools.

The inmates were trapped in the vehicle for about 20 minutes, Wanbao reported.

SCDF sent one fire engine, one red rhino, two fire bikes, four ambulances and one support vehicle to the scene.

The accident caused a traffic jam on the expressway that lasted about one and a half hours.

Police investigations are ongoing.