The explosion forced protest leader Suthep to lead protesters back to Lumphini park, from its earlier scheduled at Pathumwan for the safety of protesters.
Of the injured, 15 were admitted to Ramathibodi hospital, 8 to Hua Chiew, and 2 to Chulalongkorn.
The protesters led by protest leader Suthep, secretary-general of the People’s Democratic Reform Committee (PDRC), was on the fourth day of the Bangkok Shutdown protest campaign.
Explosive Ordnance Disposal (EOD) police arrived at the scene at 2.10 p.m. and ordered people to leave the area as they believed there might be more bombs inside.
It was not known yet if the bomb was placed on the roadside but eyewitness said a bomb was thrown from a deserted building opposite Tesco Lotus super center near the Charoenpol intersection. The bomb landed onto the road just a few minutes before the protest leader would walk pass.
Witnesses also said they saw three men in green fatigues in the deserted building.
Suthep was said to be 30 meters from where the bomb landed.
Military personnel were sent to inspect the scene of explosion. A search of the vacant area surrounding the deserted building was jointly conducted by soldiers and security guards of the PDRC.
Sporadic gunshots were also heard during the search.
The search continued at 2.15 p.m. today as security guards believed they are still hiding inside the deserted building.