The device was placed on a motorbike in Sungai Kolok, a town on the border with Malaysia.
Most of the injured are said to be Thais and Malaysian tourists. No one has admitted planting the device.
The area has been under martial law since an armed raid on an army camp in January sparked violence that left more than 50 people dead.
Violence in the region has been blamed on Islamist separatists who the government fears may have combined forces with international networks.


















