Police say disgruntled residents have set off a loud blast near a flood dike on Bangkok's border, apparently to highlight frustrations over their continued misery.
The explosion, which made a loud sound but caused no injuries, was set off last night at a barrier that separates Bangkok from Pathum Thani province.
Colonel Harn Lertthaweesap says police suspect it was the work of Pathum Thani residents who are unhappy that their community remains under water because of the dike, which is meant to keep central Bangkok safe.
Harn says it was a "loud firework, not an explosive device."
Floods caused by torrential rains since late July inundated 19 of Thailand's 77 provinces, including Bangkok. At least 594 people have died.