Riot police were retreating from the bridge near Government House to avoid confrontation with protesters from independent groups when a suspected giant firecracker was thrown toward where a group of reporters and demonstrators were gathering at 11.25am.
The blast injured a female protester and Siam Rath newspaper crime reporter Watcharin Klinmali, who sustained foot injuries.
The incident took place after more than 1,500 police officers successfully reclaimed areas on Ratchadamnoen Nok Avenue from Suan Misakawan intersection to Makkhawan Rangsan Bridge from protesters. There were no violent clashes between police and demonstrators.
Police close in on an anti-government rally site on Ratchadamnoen Avenue. Video by Thiti Wannamontha.