Two M79 grenades were fired at the Chaeng Wattana rally site late Sunday night. Two guards were slightly injured.
Explosive ordnance disposal police Monday checked the scene of the attack, which happeend at 10 pm.
A grenade fell in front of a pavilion in the rally area while anoter fell in the compound of the Air Defense Artillery Regiment. The pavilion is where Phra Buddha Isara has been staying.