Thai emergency staff help the injured after the scene of an explosion near Erawan Shrine, central Bangkok, Thailand, 17 August 2015. An explosion in a busy commercial district in the Thai capital killed at least 15 people. Witnesses said the explosion happened around 7:15 pm (12:15 GMT) at the Rajprasong Intersection, a business area famous among tourists and locals for a revered Hindu shrine. (Photo by EPA/Stringer)

Persons search for missing relatives at the scene of an explosion near Erawan Shrine, central Bangkok, Thailand, 17 August 2015. (Photo by Ritchie B. Tongo/EPA)

A general view taken from a moving train shows bodies covered in white sheets around the Erawan Shrine, central Bangkok, Thailand, 17 August 2015. (Photo by Barbara Walton/EPA)

Policemen check with sniffer dogs at the scene of an explosion on August 17, 2015 in Bangkok, Thailand. A large explosion believed to a bomb has hit central Bangkok this evening with early reports suggesting at least 16 people have died and scores more have been injured. (Photo by Nicolas Axelrod/Getty Images)

A policebooth with shattered windows near the scene of an explosion on August 17, 2015 in Bangkok, Thailand. (Photo by Nicolas Axelrod/Getty Images)

This August 17, 2015, image, released by Royal Thai Police spokesman Lt. Gen. Prawut Thavornsiri shows a man wearing a yellow T-shirt near the Erawan Shrine before an explosion occurred in Bangkok, Thailand. Prawut said he believes the man is a suspect in the blast that killed a number of people at a shrine in downtown Bangkok on Monday night. (Photo by Royal Thai Police via AP Photo)

Thai rescue workers carry an injured person after a bomb exploded outside a religious shrine in central Bangkok late on August 17, 2015 killing at least 10 people and wounding scores more. Body parts were scattered across the street after the explosion outside the Erawan Shrine in the downtown Chidlom district of the Thai capital. (Photo by Pornchai Kittiwongsakul/AFP Photo)

Thai rescue workers transport an injured person after a bomb exploded outside a religious shrine in central Bangkok late on August 17, 2015 killing at least 10 people and wounding scores more. (Photo by Pornchai Kittiwongsakul/AFP Photo)

A Thai soldier ropes off the scene after a bomb exploded outside a religious shrine in central Bangkok late on August 17, 2015 killing at least 10 people and wounding scores more. (Photo by Pornchai Kittiwongsakul/AFP Photo)

Emergency personnel work at the scene after an explosion in Bangkok, Monday, August 17, 2015. A large explosion rocked a central Bangkok intersection during the evening rush hour, killing a number of people and injuring others, police said. (Photo by Sackchai Lalit/AP Photo)

Wreckage of motorcycles are seen as security forces and emergency workers gather at the scene of a blast in central Bangkok August 17, 2015. A bomb on a motorcycle exploded on Monday just outside a Hindu shrine in the centre of the Thai capital, killing at least 12 people, police and a rescue worker said. (Photo by Athit Perawongmetha/Reuters)

Wreckage of motorcycles are seen as security forces and emergency workers gather at the scene of a blast in central Bangkok August 17, 2015. (Photo by Athit Perawongmetha/Reuters)

Blood is seen near a victim's shoe, as security forces and emergency workers gather at the scene of a blast in central Bangkok August 17, 2015. (Photo by Athit Perawongmetha/Reuters)

Bodies of victims are covered with white sheet among wreckages of motorcycles and other debris as security forces and emergency workers gather at the scene of the blast in central Bangkok August 17, 2015. (Photo by Athit Perawongmetha/Reuters)

Bodies of victims are covered with white sheet as security forces and emergency workers gather at the scene of the blast in central Bangkok August 17, 2015. (Photo by Athit Perawongmetha/Reuters)

The body of a victim is covered with white sheet as security forces and emergency workers gather at the scene of the blast in central Bangkok August 17, 2015. (Photo by Athit Perawongmetha/Reuters)

Experts investigate at the site of a blast in central Bangkok August 17, 2015. (Photo by Athit Perawongmetha/Reuters)

Experts work at the site of the blast in central Bangkok August 17, 2015. (Photo by Athit Perawongmetha/Reuters)

Bodies of victims are covered with white sheet among wreckages of motorcycles and other debris as security forces and emergency workers gather at the scene of the blast in central Bangkok August 17, 2015. (Photo by Athit Perawongmetha/Reuters)

Experts investigate at the Erawan shrine, the site of a deadly blast in central Bangkok August 17, 2015. (Photo by Athit Perawongmetha/Reuters)

The body of a victim is carried away from the Erawan shrine, the site of a deadly blast in central Bangkok August 17, 2015. (Photo by Athit Perawongmetha/Reuters)

Experts prepare to enter the scene and investigate around the Erawan shrine, the site of a deadly blast in central Bangkok August 17, 2015. (Photo by Athit Perawongmetha/Reuters)

Security forces inspect the site of a blast in central Bangkok, Thailand, August 17, 2015. (Photo by Chaiwat Subprasom/Reuters)

Security forces inspect the site of a blast in central Bangkok, Thailand, August 17, 2015. (Photo by Chaiwat Subprasom/Reuters)

Security forces inspect the site of a blast in central Bangkok, Thailand, August 17, 2015. (Photo by Chaiwat Subprasom/Reuters)

Security forces inspect the site of a blast in central Bangkok, Thailand, August 17, 2015. (Photo by Chaiwat Subprasom/Reuters)

Security forces are seen guarding a skywalk near the site of a blast in central Bangkok, Thailand, August 17, 2015. (Photo by Chaiwat Subprasom/Reuters)

A security personnel patrols a skywalk near the site of a blast in central Bangkok, Thailand, August 17, 2015. (Photo by Chaiwat Subprasom/Reuters)

The body of a victim covered with a sheet is seen as security forces and emergency workers gather at the scene of the blast in central Bangkok August 17, 2015. (Photo by Chaiwat Subprasom/Reuters)

Security forces and emergency workers gather at the Erawan shrine, the site of a blast in central Bangkok August 17, 2015. (Photo by Chaiwat Subprasom/Reuters)

Security forces and emergency workers gather at the scene of a blast in central Bangkok August 17, 2015. (Photo by Kerek Wongsa/Reuters)

Experts work at the site of the blast in central Bangkok August 17, 2015. (Photo by Kerek Wongsa/Reuters)

The body of a victim is covered with white sheet as security forces and emergency workers gather at the scene of the blast in central Bangkok August 17, 2015. (Photo by Kerek Wongsa/Reuters)

Rescue workers carry the body of a victim from the Erawan shrine, the site of a deadly blast in central Bangkok August 17, 2015. (Photo by Kerek Wongsa/Reuters)

Experts investigate the remains of destroyed motorcycles at the Erawan shrine, the site of the blast in central Bangkok August 17, 2015. (Photo by Kerek Wongsa/Reuters)

Experts investigate the remains of destroyed motorcycles at the Erawan shrine, the site of the blast in central Bangkok August 17, 2015. (Photo by Kerek Wongsa/Reuters)

Medical workers rush the victim of a blast at the Erawan shrine to a nearby hospital in central Bangkok August 17, 2015. (Photo by Kerek Wongsa/Reuters)

Thai Buddhist monks walk past near the scene of a blast in central Bangkok August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

Experts investigate the Erawan shrine at the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

Experts investigate the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

Experts investigate the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

Experts investigate the Erawan shrine at the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

Experts investigate the Erawan shrine at the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

An expert investigates the Erawan shrine at the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

Experts investigate near the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

Military personnel stand guard near the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

Experts investigate debris near the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

Police officers clean a street near the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

Workers clean a street near the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

Experts investigate the Erawan shrine at the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

Broken glass from the blast is pictured near the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

Police officers clean a street near the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

People hold up signs and flowers near the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

A tourist takes a picture near the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

Tourists walk near the site of a deadly blast in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

A police officer stands in front of the Erawan shrine, the site of a deadly blast, in central Bangkok, Thailand, August 18, 2015. Thai authorities said on Tuesday they were looking for a suspect seen on closed-circuit television (CCTV) footage near the renowned shrine where a bomb blast killed 22 people, including nine foreigners from several Asian countries. (Photo by Athit Perawongmetha/Reuters)

A member of military personnel stops the media from taking pictures at the Erawan shrine, the site of a deadly blast, in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)

An expert cleans an altar with a statue of Hindu god Brahma at the Erawan shrine, the site of a deadly blast, in central Bangkok, Thailand, August 18, 2015. (Photo by Athit Perawongmetha/Reuters)