"The security agencies have collaborated with intelligence agencies from a lot of countries and have come to the same preliminary conclusion that the incident is unlikely to be linked to international terrorism," Thai junta spokesman Colonel Winthai Suvaree told reporters.
Nobody has claimed responsibility for the attack at the Erawan Brahma temple, one of the most popular tourist attractions in Bangkok, that killed 20 people, including five Chinese, and injured more than 100 others on Monday night.
Colonel Winthai said Thai security agencies were in close touch with other countries. He said the preliminary investigation into the attack showed that the Chinese people were not the target because other nationalities too were hurt.
Nationals from Hong Kong, the UK, Indonesia, Malaysia and Singapore were also among the foreigners killed in the attack.
Thailand's national police chief Somyot Poompanmoung gave a detailed profile of the mysterious assailants, saying there were more than 10 involved and they carefully planned the attack.
"This blast was carried out by teams...there was a survey team, a protection team, material providing team and exit team," Somyot told reporters.
Police spokesman Lt Gen Prawut Thawornsiri said he is confident that some Thais were involved.
He also referred to the man in a yellow T-shirt captured by CCTV cameras and for whom an arrest warrant has been issued, saying the suspect did not use Thai language in communicating with the motorcycle taxi driver he hired.
The police are now hunting for two men and a woman captured on the camera standing near the prime suspect for interrogation.
Thai police said they did not know if the man suspected of planting the bomb was in the country or not, as they asked Interpol for help.
Thai police last evening released a sketch of a young bespectacled "foreign man" who carried out the bombing and is believed to be part of the over 10-member network.
Authorities also announced a reward of 1 million baht (approximately Rs 18 lakh) for information leading to his arrest.
The sketch shows a young man in black-rimmed eyeglasses with bushy, dark hair and a light complexion. The warrant issued by Bangkok's Southern Criminal Court describes him as tall, with a pointed nose and thick lips.
The sketch of the suspect is based on the CCTV footage and a description provided by the motorcycle taxi driver who is believed to have given him a ride on Monday night.
The Brahma temple was reopened on Wednesday for worshippers and tourists two days after the blasts.
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