Two women were slightly injured after an explosive device went off in front of the National Theatre on Monday night.
The object went off at 8.30pm near Sanam Luang and police said two women were slightly injured. They were identified as Chanphen Wutthiekpaibul and Kanchana Booncheep.
A piece of what appears to be a pipe bomb is found at the scene.
They were sent for treatment at a makeshift hospital tent operated by the army at Sanam Luang.
Explosive ordnance disposal police and Chana Songkhram police are at the scene and the area is sealed off.
Officials have not identified the device but a picture indicated that it was a pipe bomb.