Seven vocational students have been charged with the possession and transport in public of explosives and knives following a blast in the Rama 9 area of Bangkok on Friday in which two municipal workers were injured.

Citing CCTV footage and witness accounts, the metropolitan police say that the students hid a “Ping Pong” bomb in shrubs on Rama 9 Soi 57/1. The device subsequently exploded, injuring the two municipal workers working in the area.

However, some of the suspects argued that they had just passed through the area, as they were shown riding motorcycles in the CCTV footage.

Police claim that one of the suspects admitted that he had made the improvised explosive device.

Police have ruled out any connection of the group to other explosions in Bangkok on Friday.

Two suspects, who are natives of the southern province of Narathiwat, were apprehended in Chumpon province as they were travelling home by bus from Bangkok.