After an M79 grenade was launched at the Central Airport Plaza Shopping Center on March 23, Chiang Mai Provincial Police commander Pol. Maj Gen Sommai Kongwisut announced that security around the city has been tightened, measures have been stepped up at City Hall and the Court buildings, patrols have been increased and checkpoints instituted around the city.

The M79 grenade launched at the shopping center was presumably aimed at the police box but hit the wall of the building. Police believe it was shot from an overpass near the shopping center. The police are viewing CCTV cameras to single out suspects in the attack.

There have been four bomb threats or attacks, with giant fireworks being shot at the Bangkok Bank ATM machine in Chang Phuak and the M79 attack on Central Aiport Plaza. The Chiang Mai Construction Co. Ltd owned by Kanaen Supha, the father in law of politician Newin Chidchob was also attacked.

The fourth and latest attack was a grenade planted at a Bangkok Bank ATM machine in San Kamphaeng on March 25. Locals informed the police that a grenade had been found in the bin near the Sai Wattanatham San Kamphaeng Bangkok Bank ATM machine. Police discovered an M76 grenade and proceeded to disarm it and remove it.

Chiang Mai Provincial Police commander Pol. Maj Gen Sommai Kongwisut believes the attacks could be the work of people trying to foment fear and chaos and has stepped up patrols and checkpoints around the city.