Thai Officials have yet to blame any group for the bombing at the Erawan shrine on August 17 evening, which the government called a bid to destroy the economy. No one has claimed responsibility.
National police chief SomPoompanmuang told reporters the attack was unprecedented in Thailand. He said the blast was caused by a pipe bomb.
Three Chinese were among the dead, the official Xinhua news agency said. Two Hong Kong residents, two people from Malaysia and one person from the Philippines had also been killed, officials said. Scores of people were wounded, including many from China and Taiwan.
Thai forces are fighting a low-level Muslim insurgency in the predominantly Buddhist country's south, but those rebels have rarely launched attacks outside their heartland.
"This does not match with incidents in southern Thailand. The type of bomb used is also not in keeping with the south," Royal Thai Army chief and deputy defence minister General Udomdej Sitabutr said in a televised interview.
More than 6,500 people have been killed in the long-running insurgency since 2004.
Thai national police spokesman Prawut Thavornsiri said the death toll stood at 22 from the bombing, with 123 people wounded.
Police teams were deployed to the blood splattered site early on August 18, with some wearing white gloves and carrying plastic bags, searching for clues.
