International terrorists were not suspected of a bomb attack in Bangkok this week that killed 20 people and China was not the target, Thai authorities said on Thursday, as police said they believed at least 10 plotters were involved.
There has been no claim of responsibility for the Monday evening attack on a famous shrine crowded with tourists, which the government has said was designed to wreck the economy. Authorities have not blamed any group for carrying out Thailand's worst bombing.
"Security agencies have cooperated with agencies from allied countries and have come to the preliminary conclusion that the incident is unlikely to be linked to international terrorism," said Colonel Winthai Suvaree, a spokesman for the country's ruling junta, known as the National Council for Peace and Order.
The Erawan shrine is particularly popular with tourists from China and other East Asian countries, and 11 foreigners were among the dead, including six from mainland China and Hong Kong, but Winthai said Chinese tourists were not believed to have been the target.
He did not elaborate or say who might have been responsible.
China is an important ally and trade partner for Thailand and the biggest source of foreign tourists.
Police said on Wednesday a young man who was caught on grainy security camera footage planting the backpack bomb was believed to be European or Middle Eastern.
The apparent elimination of foreign militant involvement will feed speculation that either Muslim separatists waging a low-intensity insurgency in southern Thailand, or domestic political activists, were involved.
Police said at least 10 people were suspected of involvement in the attack and they appealed to Interpol for help in finding the man caught in the video footage.
National police chief Somyot Pumpanmuang said the investigation showed the attack was planned at least a month in advance and a "big network" was involved.
"This includes those who looked out on the streets, prepared the bomb and those at the site and ... those who knew the escape route. I believe there must have been at least 10 people involved," Somyot told reporters.
He did not say who he believed the plotters were or elaborate on the investigation.
'REGION IN DANGER'
Police said they sent Interpol an image of the man in a yellow shirt and shorts, with thick, black hair and a wispy beard and glasses caught in video footage just before the blast.
Checks at airports and other exit points found that no one matching the description of the main suspect had left the country since the attack, police said.
Prime Minister Prayuth Chan-ocha told reporters the man seen in the CCTV footage was in disguise, a theory that police have yet to agree on.
"The criminal altered his appearance," Prayuth said. "It means there was preparation. It was as though he knew a camera was going to be there."
Prayuth said earlier the attack was Thailand's problem and should be resolved internally but on Thursday he said it signaled a threat to the whole region.
"This event has never happened in Thailand, it is dangerous for ASEAN," he said, referring to the Association of South East Asian Nations.
The blast comes at a sensitive time for Thailand, which has been riven for a decade by a sometimes-violent struggle for power between political factions in Bangkok.
A parliament hand-picked by a junta that seized power in a 2014 coup is due to vote on a draft constitution next month.
Critics say the draft is undemocratic and intended to help the army secure power and curb the influence of elected politicians. The government has promised to restore democracy late next year.
The Erawan shrine, which is dedicated to Hindu deities but is popular with Buddhists in Thailand, has since reopened.
Visitors have left messages of condolence, flowers and candles at the site.
