A bomb exploded at a popular shrine in central Bangkok during evening rush hour Monday, killing at least 18 people, injuring more than 100 and leaving body parts strewn across the streets of a neighborhood full of five-star hotels and upscale shopping malls.
No one immediately claimed responsibility for the blast, which caused the worst carnage of any single attack in recent memory in the Thai capital.
Bangkok has been relatively peaceful since a military coup ousted a civilian government in May last year after several months of sometimes violent political protests against the previous government.
The area around Bangkok's Erawan Shrine is filled with hundreds of tourists, office workers and shoppers at any given time. Police said the bomb was made from a pipe wrapped in cloth.
"Whoever planted this bomb is cruel and aimed to kill," said national police chief Somyot Poompummuang. "Planting a bomb there means they want to see a lot of people dead."
The shrine is at a major intersection that was the center of many contentious political demonstrations in recent years, raising questions about whether the bombing was politically linked. But police said it was too soon to determine the attack's motive.
Security video showed a powerful flash as the bomb exploded at around 7 p.m.
At least 18 people were confirmed dead and 117 injured, according to the Narinthorn emergency medical rescue center.
The dead included Chinese nationals and a Filipino, Somyot said.
Anusit Kunakorn, secretary of the National Security Council, said Prime Minister Prayuth Chan-ocha, the former army chief who orchestrated the May 2014 coup, was closely monitoring the situation.
"We still don't know for sure who did this and why," Deputy Prime Minister Prawit Wongsuwon told reporters. "We are not sure if it is politically motivated, but they aim to harm our economy and we will hunt them down."
Although Bangkok has seen a period of relative calm since the coup, there has been some tension in recent months, with the junta making clear that it may not hold elections until 2017 and wants a constitution that will allow some type of emergency rule to take the place of an elected government.
Stirring controversy has been former Prime Minister Thaksin Shinawatra, who was ousted in a 2006 coup and fled the country to avoid a corruption conviction. Last week, Thaksin posted a message on YouTube urging his followers to reject the draft constitution because he said it was undemocratic.
The draft charter is supposed to be voted on next month by a special National Reform Council. If it passes, it is supposed to go to a public referendum around January.
Another source of recent tension has been the annual military promotion list, with the junta's top two leaders — Prime Minister Prayuth and Deputy Prime Minister Prawit — widely believed to be supporting different candidates.
The reshuffle, which comes into effect in September, has traditionally been a source of unrest, as different cliques in the army, usually defined by their graduating class in the military academy, seek the most important posts to consolidate their power.
While bombings are rare in Bangkok, they are more common in southern Thailand, where a Muslim separatist insurgency has been taking place for several years. Thailand is predominantly Buddhist, but the three southern provinces where the insurgency has flared are Muslim majority.
The last major bombings in Bangkok occurred on New Year's Eve at the end of 2006, when a series of explosions at celebrations around town killed at least three people and wounded dozens.
Those bombings occurred just three months after the coup that ousted Thaksin, and there was speculation that his supporters carried out the attacks in revenge. However, the bombings were never solved.
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