More than 60 people wounded on Wednesday after a car bomb exploded near a supermarket in the southern Thailand city of Pattani.
Two bombs went off at 2:00pm local time outside the Big C, a busy supermarket near the town centre, scattering debris over a wide area and sending up a column of black smoke.
The first device was packed inside a motorcycle in the car park, officers said, spreading panic among shoppers.
"The second blast was a car bomb," said Pattani police commander Major General Thanongsak Wangsupa.
Deputy director of Pattani Hospital Arun Prasertsuk told a local television channel that 21 victims remain in hospital with serious injuries, and others were discharged after receiving treatment.
The bomber is believed to have left the scene before the explosion, Deputy Police Chief Rewat Srichantub said. He said it was the first car bomb in Pattani since August.
There has been no claim of responsibility for the attack.
Peace talks to end violence
The country's south has been plagued by violence for over a decade as ethnic Malays battle the Buddhist-majority state for more autonomy.
Talks between the Thai junta and an umbrella group claiming to represent the Malay fighters have staggered along for years without any result.
The government recently rejected a conditional offer for peace talks from one of the main insurgent groups, the Barisan Revolusi Nasional, which demanded international mediation or observation.