Army commander Udomdej Sitabutr vehemently denied speculation spreading Monday that the explosions at Siam Paragon on Sunday were an attempt by the government to prolong martial law.
"The state would never do that. We do things honestly. We don't create situations," he said.
Security has been stepped up at the blast site, near a walkway linking the Siam Paragon shopping centre to BTS Siam. (Photos by Wichan Charoenkiartpakun)
Rumours that the Paragon blasts were staged to justify the enforcement of martial law spread widely Tuesday.
Gen Udomdej played down suggestions the incident was aimed at challenging the government and the National Council for Peace and Order (NCPO), saying motives have not yet been established and the incident could be a prank by rogue groups.
The army named three groups it believes could be responsible for the two explosions, while police said they are "90% certain" the attack is politically motivated.
- Tourists carry on: Bombing 'is typical Thailand'
According to a source, the three groups the army suspects are those affected by the NCPO's crackdown on bribery, extortion and corruption; the political group dissatisfied with the military government; and police officers who are displeased after recent transfers.
"With an incident like this, the NCPO will focus on groups with political leanings. Some people are not happy with the impeachment of former prime minister Yingluck Shinawatra and have made remarks that make them suspects," said the source.
Forensic officials and investigators from Pathumwan police station collect evidence from the scene of the blast outside Siam Paragon.
However, Pol Gen Chakthip Chaichinda, deputy national police chief, said it was too early to conclude whether the explosions were politically motivated.
"Ninety percent of similar incidents have been politically motivated," he said.
There were at least two people involved in Sunday's explosions and warrants for their arrest are expected to be issued this week, he added.
Two homemade bombs exploded on a walkway between Siam BTS and Siam Paragon shopping centre at 8.20pm on Sunday, sparking panic among shoppers and tourists. Two people were injured.
Police initially reported the blasts were caused by a transformer explosion, but later revealed they were caused by two pipe-bombs hidden behind an electrical control panel.
Police and the military said the bombs were low-impact devices and could not have caused loss of life.
Police spokesman Pol Lt Gen Prawut Thawornsiri said the explosive devices were similar to those used in Min Buri last year, but said there is no evidence linking the blasts at the moment.
First Region Army commander Lt Gen Kampanat Ruddit said people who have made threats of violence are under the most suspicion.
"Inviting them to an army unit doesn't work and is likely to lead to opposition. So I think we will drop by their houses for a visit and seek cooperation from them. We have to solve problems. If I have a chance, I will talk to them myself," he said.
But Worachai Hema, a red-shirt leader and former Pheu Thai MP, said the red shirts are not behind Sunday's explosions.
He said the violence does not match with red shirts' aims because the group wants the country to return to peace and order as soon as possible so that elections can proceed.
According to Mr Worachai, one of two groups could be responsible.
The first is those who are dissatisfied with the government and the NCPO, and the other is those who think the explosions could be used as leverage to prolong enforcement of martial law, he said.
Prime Minister Prayut Chan-o-cha Tuesday condemned the blasts and urged the public to give authorities enough time to solve the case.
Gen Prayut said it was too early to conclude whether the incident was politically motivated.
"An attack like this is a criminal offence, even if it is politically motivated. People can't resort to violence because it is against the law.
"People must understand that differences of political views and breaking the law are two separate issues," he said.
He said security would be intensified following the blasts and called on the public to report any suspicious objects or individuals.
Deputy Prime Minister and Defence Minister Prawit Wongsuwon said security would be tightened in the wake of the explosions.
"I am sorry if people will be deprived of some conveniences. We have to intensify measures for security," he said.