Four bomb attacks took place without causing casualties late Wednesday night and early yesterday in Bangkok, in what police described as possibly politically motivated and a potential precursor to increased violence.
The four attacks occurred at the Chulabhorn Research Institute, Siam Commercial Bank headquarters, the home of a Constitutional Court judge, and the Defence Ministry.
They occurred in succession, starting at around 9pm, after a Constitutional Court ruling had earlier ended the term of caretaker Prime Minister Yingluck Shinawatra.
Deputy Bangkok police chief Maj Gen Chayut Thanathaweerat said the attacks on medical and financial institutes signified a potential upswing in political violence. More policemen will be deployed in areas at risk and political rally sites, he added.
He said police had a database of potential suspects, but were not sure whether those behind each individual attack was conducted by the same group of people. Police needed time to gather evidence and intelligence before making a conclusion on who had masterminded the attacks, he added.
In the first attack, two M-79 rounds were fired into the Chulabhorn Research Institute compound, located on Vibhavadi Highway, and also hitting the ninth floor of Chulabhorn Hospital. Along with the building, a parked taxi was also damaged.
Within 30 minutes, a lone M-79 round hit the eighth floor of the Siam Commercial Bank complex. Explosives Ordnance Disposal (EOD) police said it was possibly fired from Ratchadaphisek Road at the front of the building.
A ping-pong ball explosion at the Defence Ministry compound near Sanam Luang caused minor damage, said Pol Colonel Kamthorn Uei-charoen, an EOD unit commander.
He said the EOD was not notified of the attack by local police, who deemed it to be a light, non-lethal attack.
As for research-institute attack, Kamthorn said the M-79 rounds were possibly fired from a moving vehicle at a distance of 180-200 metres.
It will be determined later whether the rounds were fired from the ground level on the highway or from an elevated position on the tollway overhead, he said.
At around 1am, an M-67 hand grenade was lobbed into the house of Constitutional Court judge Supoj Khaimuk. The house is located in Lat Phrao Soi 34. The blast damaged a parked car and the roof of the garage.
Earlier that day, gunshots were fired from a taxi into a group of anti-government movement People’s Democratic Reform Committee supporters at the movement’s Lumpini Park base.
PDRC guards reportedly saw the daytime shots fired from the taxi as it travelled along a flyover at the Sala Daeng intersection.
Chulabhorn Hospital condemned the double M-79 attack on the research institute, describing the act as inhumane. It said medical institutes were protected by international laws, including during combat.
A deputy police spokesman, Maj-General Anucha Rommayanant, said security had been heightened at key landmarks and symbolic locations, and more checkpoints had been erected in an attempt to intercept the transport of weapons.
Anucha said the number of officers stationed outside the homes of high-profile judges had been increased.