( dpa ) - Suspected separatists detonated a bomb Tuesday morning planted on a stolen motorcycle parked near Yala's popular morning market, injuring 37 civilians, six of whom were listed is critical condition, police said.
The explosion occurred at 6:40 am when the market was crowded with food vendors and early-morning shoppers, said Yala Police Colonel Poomphet Phiphatphetpoom.
The bomb, detonated by mobile phone, was hidden inside a motorcycle reported stolen on Monday, Poomphet said.
Tuesday's blast follows on the heels of a violent attack Monday on a Thai patrol in nearby Narathiwat province that left eight soldiers dead.
The ambushed squad - a protection unit for teachers, who are frequent targets of separatist insurgents - was surprised by an unknown number of insurgents in the Chanae district of Narathiwat province, Army spokesman Colonel Akara Thiprote said.
The insurgents, estimated at more than 20 strong, detonated a road bomb under the army Humvee carrying the troops, then emerged from the jungle to execute the soldiers, decapitating one of the victims.
"This is a big loss for the army," Akara said. "It is one of our worst days. We will do our utmost to hunt down the killers."
The fighters who ambushed the patrol were likely to be living locally in the tight-knit Muslim communities in the area, making it tricky for security forces to identify them, he added.
"We really need some good intelligence to guide us," Akara said. "These people will bury their guns and turn into ordinary villagers before we reach them. It is not easy."
The patrol had been returning to base after escorting teachers to a government school. Teachers have been frequently targeted because the separatists consider them to be agents of a central government dominated by the country's Buddhist majority.
Thailand's deep South - comprising the three border provinces of Narathiwat, Pattani and Yala - has been in turmoil since January 2004 when Muslim militants raided an army arms depot in Narathiwat and stole more than 300 weapons, unleashing a military crackdown on the long-simmering separatist movement.
The region has seen a surge in violence ever since with more than 2,600 people falling victim to clashes, shooting, bombings and beheadings.
Many Muslims are caught between fear of the insurgents, respect for their culture and the demands for loyalty from Bangkok. Most deaths have been of Muslims.