Thai Prime Minister Prayut Chan-o-cha has ordered a probe into the bomb attacks at several locations in Bangkok yesterday, which took place as the city hosted a regional summit attended by senior ministers from around the world.
Police believe homemade bombs caused the six explosions which left four people slightly injured and rush-hour commuters scrambling. A seventh unexploded device was later recovered by the authorities.
Mr Prayut condemned the attacks, and urged the public not to panic. "We must demonstrate our collective effort to fight against those who intend to harm the country. Let's not have them stand with us in society," he said in a statement yesterday.
Two small explosive devices went off near the busy BTS Skytrain Chong Nonsi station in central Bangkok before 9am, with one explosion heard in front of the King Power Mahanakhon Building, which is near the elevated station, and another under the station.
A spokesman for the Erawan Emergency Medical Centre said two of the injured were working at the Mahanakhon building.
Commuters later posted photos of a shattered glass screen at the station on social media.
"I was just stepping out of the station and I heard a very loud bang. It was very scary. There was a flash of light and some smoke. People were panicking and rushing out," tweeted @muchmuchmellow.
There was also an explosion in Suan Luang, a residential area in the city. "Residents said they saw some students drop something (before the explosions), so we are chasing the lead," police officer Teerapong Wongratpitak told The Straits Times, as officers combed the area for clues.
Several explosions were also heard at the government complex in Chaeng Wattana on the outskirts of Bangkok, but nobody was injured.
On Thursday, police said they had found two fake bombs near the Centara Grand and Bangkok Convention Centre, where the 52nd Asean Foreign Ministers' Meeting and related gatherings were being held. Two men have been arrested in connection with the incident.
Security has since been tightened in the hotel's vicinity and at the nearby Central World shopping mall.
At a news conference yesterday, Mr Prayut pointed to the "old group" as possible culprits behind the explosions. He was referring to his political rivals the Red Shirt group, comprising supporters of former prime ministers Thaksin and Yingluck Shinawatra.
"But I am not ruling out other possibilities," he added. "Whoever did this, they want to destroy the country. They shouldn't have a place in this country."
Former army chief Prayut first came into power in a May 2014 coup and led the country's military government for five years. He was elected to a second term after Thailand's general election in March, thanks to the rubber stamp Senate and the success of the pro-military Palang Pracharat Party.
However, police chief Chakthip Chaijinda told reporters that initial investigations pointed to a group of southern Muslim insurgents who were behind a series of bombings in many parts of Thailand in August 2016 that left four people dead and dozens injured. According to him, the fake bomb incident on Thursday was linked to yesterday's bombings.
"The situation is controllable," he assured the media.
- Additional reporting by Tan Hui Yee