The bombs that exploded in a busy Bangkok street yesterday were intended for "foreign nationals" in Thailand, national police chief Priewpan Damapong said.
Bystanders watch as a bomb disposal expert approaches the attack site in front of Kasem Phithaya School on Sukhumvit Soi 71. PRAKIT JUNTHAWONG
He did not give further details but said only that the targets were not Thais.
The blasts injured five people including a bomb suspect carrying an Iranian passport who blew off his own legs.
Another Iranian suspect was arrested at Suvarnabhumi airport hours after the incident as he was about to leave for Malaysia. He is one of three suspects thought to be involved.
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The United States and the United Kingdom yesterday reissued their travel warning for their nationals in response to the blasts.
Israel's Defence Minister Ehud Barak blamed the series of explosions on Iran.
Mr Barak was quoted in The Jerusalem Post as saying the bomb blasts were part of an attempted terrorist attack perpetrated by Iran.
"The attempted terror attack in Thailand proves once again that Iran and its proxies continue to operate in the ways of terror and the latest attacks are an example of that," Mr Barak said while on a state visit to Singapore.
The incident came one day after near simultaneous attacks on Israeli diplomats in Georgia and India. Israel pointed the finger at Iran for the attacks but Teheran denied responsibility.
Despite Mr Barak's accusations against Teheran, the Israeli Foreign Ministry said yesterday Israel was in contact with the authorities in Bangkok and was still awaiting confirmation that the man involved in the blasts was indeed Iranian.
Will Hartley, head of the terrorism and insurgency Centre, IHS Jane's, said the fact that the man who lost his legs in the blast possessed an Iranian passport could possibly lend credence to Israel's allegation that Iran is waging some kind of international campaign.
He said the attacks in India, Georgia and now Thailand have all been highly amateurish.
"[They] lack the sophistication that would normally be expected from an operation executed by either Hezbollah or Iran's own external operations wing, the Quds Force," Mr Hartley said.
Two explosions were heard shortly after one another around 2.20pm between soi Pridi Bhanomyong 31-35 off Sukhumvit 71 Road.
A passport found at one of the blast sites identified the severely injured man at the scene as Saeid Moradi, 28, from Iran.
The suspect reportedly threw a grenade at a taxi in Pridi Bhanomyong Soi 31 after the taxi driver failed to stop to take him.
He ran away from the scene to the front of Kasem Phithaya school on Sukhumvit 71 Road and allegedly hurled a box packed with explosives at a police patrol vehicle which was heading towards him.
The device hit a passing pickup truck, bounced back, fell next to him and exploded.
Three bystanders, also injured in the explosions, were identified as Apichart Khamlue, 33, Kangwal Horprasartthong, 80, and Suthathip Sajjadamrong, 62.
Mr Moradi was sent to Chulalongkorn Hospital.
Police later arrested another of the remaining suspects at Suvarnabhumi airport about 6.20pm. The man, identified as Mohummad Hazaei, 42, is holding an Iranian passport, Metropolitan Police chief Winai Thongsong said. Mr Hazaei was due to board an Air Asia flight to Malaysia.
Mr Hazaei refused to give testimony to the police and asked for a translator, Pol Lt Gen Winai said.
Pol Gen Priewpan yesterday said an investigation found Mr Hazaei arrived in Thailand on Feb 8 on the same flight as Mr Moradi and another suspect who is on the run. The three came from Malaysia and landed in Phuket.
Immigration police chief Wibul Bangthamai said he had instructed authorities at all international airports and checkpoints to beef up security check to prevent the remaining suspect from escaping.
Police searched the two-storey house where the first explosion took place and found about 4 kilogrammes of C4 explosives planted in two radio receivers. Pol Lt Gen Winai said they are the same type as the three bombs which exploded at the rented house, a taxi, and in front of the school. A bomb squad source said each bomb could cause serious damage in a 40m radius. The source said such bomb-making methods had never been found in Thailand before.