Two M79 grenades fell on the roofs of the head offices of the National Anti-Corruption Commission and the Government Lottery Office in Nonthaburi late Monday night, police said.
Witnesses told police that they heard three explosions at near NACC and GLO offices in Sanam Bin Nam area in Nonthaburi at about 10:30 pm.
Explosive ordnance disposal officers checked the scene and found traces of two grenades. The first one landed on the glass roof of the NACC, causing a hole. The other one landed on the concrete roof of the GLO office.
Police believe the attackers want to fire the grenades at a red-shirt group rallying in front of the NACC but miscalculated the projectile.