Man in yellow shirt is Bangkok — Police tell AP

The police said in a statement that the bomb was probably “the work of at least 10 people and at least one month’s planning, with Thai people involved”.

“He didn’t do it alone for sure”, national police chief Somyot Poompanmoung was quoted by The Associated Press as saying. “It’s a network”, he added, without giving further information. “Clearly a group like that has the motivation and the military skills and capability and bomb-making techniques for this”, said Davis of IHS Jane’s, though he cautions there is as yet nothing suggesting the group’s involvement.

Two men identified as suspects by police investigating the Bangkok bombing have come forward to claim they were only in the area as tour guides.

It accuses an “unnamed foreigner” of conspiracy to commit “premeditated murder” and weapons offences.

A reward of 1 million Thai Baht ($28,000) is being offered for information leading to the suspect’s arrest, he said.

Police are now searching for a “foreign” man who was seen on CCTV footage leaving his backpack behind at the site of the explosion just minutes before it occurred.

Prime Minister Prayuth Chan-ocha said the attack signaled a threat to the region.

Thai authorities had at first been reluctant to seek help in the investigation into the blast but on Thursday appealed for Interpol’s assistance in finding the man accused of being the prime suspect.

However, our correspondent says there are indications the main suspect was driven to the airport after the attack and may well have flown. It houses a statue of Phra Phrom, or four-faced Lord Brahma, the Hindu god of creation. Islamic State/Katibah Nusantara The Islamic State has made it clear it wishes to export its jihad or inspire militant attacks outside of its base in Iraq and Syria, and security experts say it formed a Malay-speaking Southeast Asian unit called Katibah Nusantara for this objective.

The attack, in a popular tourist hub and close to upscale shopping malls, claimed the lives of at least 13 foreigners – from China, Hong Kong, Britain, Indonesia, Singapore and Malaysia.

Sunny Burns, an Australian model and actor, was horrified when he saw his photographs being compared on social media with a man who carried out a deadly bomb blast in Bangkok’s commercial district. No-one was hurt, but the authorities have not ruled out a link between the incidents.

He said that if the men in red and white shirts were innocent and aware of the suspicions against them, they should report to police.

Three days after the attack at a revered shrine in central Bangkok killed 20 people, authorities appeared to have few solid leads into the perpetrators of the deadliest attack in Thailand’s recent history.

“The motive is to discredit the government and make it unacceptable to other countries when it comes to safety in the country,”Mr Somyot said, quoted in the Bangkok Post”.