A bomb on a motorcycle exploded on Monday just outside a Hindu shrine in the centre of the Thai capital, killed at least 18 people, several of them foreign citizens, and wounded more than 100, Thai media reported. Most of the injured were tourists from China and Taiwan, media said.
There was no immediate claim of responsibility. Thai forces are fighting a low-level Muslim insurgency in the predominantly Buddhist country's south, although those rebels have rarely launched attacks outside their ethnic Malay heartland.
Monday's blast was near the Erawan shrine in Ratchaprasong, an area containing a major intersection and large shopping center.
So far, no Israeli casualties have been reported. Thailand is a popular destination among both Israeli families and young backpackers and thousands of Israelis are estimated to currently be in the country.
While initial suspicion might fall on Muslim separatists in the south, Thailand has been riven for a decade by an intense and sometimes violent struggle for power between political factions in Bangkok.
Occasional small blasts have been blamed on one side or the other. Two pipe bombs exploded outside a luxury shopping mall in the same area in February, but caused little damage.
Police said that attack was aimed at raising tension when the city was under martial law.
The army has ruled Thailand since May 2014, when it ousted an elected government after months of at times violent anti-government protests.
The Erawan shrine, on a busy corner near top hotels, shopping centres, offices and a hospital, is a major tourist attraction, especially for visitors from East Asia. Many ordinary Thais also worship there.
The intersection was the site of months of anti-government protests in 2010 by supporters of ousted former Prime Minister Thaksin Shinawatra. Dozens were killed in a military crackdown and a shopping centre was set ablaze.