Three bomb attacks minutes apart killed 10 people and wounded more than 100 on Saturday in the main town in Thailand's insurgency-hit far south.
The blasts hit the centre of Yala town around midday as families were out shopping, in the most deadly attack in five years in the Muslim-majority south of mainly Buddhist Thailand.
Several shop houses near the blast sites were set on fire and many parked cars and motorcycles were damaged by the powerful explosions.
"There were three bombs that exploded, the first is a car bomb and the second and third bombs were hidden in motorcycles," said Colonel Pramote Promin, spokesman for the southern army region.
Bomb squad officers were seen inspecting the mangled car wreckage at the site of the car bomb as firefighters doused blazes nearby.
Rescue workers helped bloodied victims and searched for other wounded people as smoke filled the street. Ten people were in critical condition with severe burns, the public health ministry said.
A Yala city policeman added: "The bombs went off about 10 minutes apart."
A nurse in the emergency unit of Yala provincial hospital told AFP nine dead and 112 wounded had been admitted, but police later said the death toll had risen to 10.
One policeman was wounded in a separate motorcycle bomb attack in Mae Lan district of neighbouring Pattani province, police said.
A complex insurgency, without clearly stated aims, has plagued Thailand's far south near the border with Malaysia since 2004, claiming thousands of lives, both Buddhist and Muslim, with near-daily bomb or gun attacks.
However, they are rarely as deadly as Saturday's explosions.
The insurgents are not thought to be part of a global jihad movement but are instead rebelling against a long history of perceived discrimination against ethnic Malay Muslims by successive Thai governments.
A string of shootings in Yala province left 10 people dead in August 2007, while nine people were killed by a bomb in a village in January last year, also in Yala.
Struggling to quell the unrest, authorities have imposed emergency rule in the region, which rights campaigners say effectively gives the army legal immunity.
The military last week admitted troops had shot dead four Muslim villagers on their way to a funeral due to a "misunderstanding" in late January after apparently fearing they were under attack from militants.
One of the region's deadliest incidents occurred on October 25, 2004, when seven people were shot dead as security forces broke up a protest in the town of Tak Bai, and 78 more suffocated or were crushed to death in trucks while being transported to a detention centre.
Rights groups have said the failure of Thai authorities to hold security forces to account over the deaths has fuelled further violence and alienation in the southern region.