Thirty-eight protesters were injured when an unknown assailant lobbed a grenade at the procession led by People's Democratic Reform Committee secretary-general Suthep Thaugsuban on Banthad Thong Road at noon Friday.
As of 8:00 pm, Bangkok Metropolitan Administration's Erawan Emergency Medical Services Centre reported that 38 people were injured in the bomb attack on Banthad Thong Road.
Twelve of the injured were rushed to the Ramathibodi Hospital, 12 to Huachiew Hospital, three to the BMA Central Hospital, and 11 to Chualongkorn Hospital.
The explosion also damaged a pick-up truck.
Several protesters were seen covered in blood on the Bluesky satellite TV that broadcast the incident live. Some of them were rushed away in a pick-up truck and a Siriraj Hospital ambulance rushed to the scene to pick up the rest of the injured. Bullet holes could clearly be seen on the pick up's trunk.
Protesters were seen running into a deserted building, trying to find the assailant.
PDRC security officers said the bomb was lobbed from a three-storey building. The building is in the process of demolition.
The attack happened near Lotus Charoenphol shopping mall.
It happened before Suthep was about to pass the area.
Military police from the Army rushed to the scene to inspect the explosion. Army officers were seen on Bluesky showing what appeared to be bomb shrapnel to reporters.
Satit Wongnongtaey, a protest leader, said he would discuss security measures with Suthep followng a bomb attack on Banthad Thong Raod and attacks at the Chaeng Wattana rally site.
Satit said the bomb attack against the march by Suthep on Banthad Thong Road did not terrify the people.
He said caretaker Prime Minister Yingluck Shinawatra must take responsibility for the violence.
Army Ordnance Corps officers found an assortment of war weapons in a room of the deserted building from which a grenade was lobbed at protesters on Banthad Thong Road.
Army Ordnance officer and Bluesky and another TV station reporters went inside the building to check and found a bomb’s safety pin and an assortment of war weapons.
Bluesky reported that there were also a refrigerator, clothes, bath towel, foam foods packages, and a red cap in the room.
Footage of Bluesky also showed a whiteboard with details plans of attacks against certain vehicles with dates and times.