A bomb killed two people in southern Thailand on Sunday and police said they had defused other devices, apparently placed by Muslim separatists showing their capacity to strike despite a failed attack on a marine base last week.
The insurgency in Thailand's south by ethnic Malay separatists flared up in 2004 and more than 5,300 people have since been killed in the provinces of Pattani, Yala and Narathiwat.
On Wednesday, in the deadliest incident in the area in nine years, up to 60 insurgents attacked a marine base in Narathiwat. However, the authorities had been tipped off and marines killed 16 of the assailants, with no loss of life among the military.
That was seen as a setback for the rebels, athough some analysts had warned it would make them more determined, and retaliation came quickly.
"The bomb was hidden in a fruit basket placed by a clock tower in the city of Pattani. It killed two defence volunteers and injured a policeman. Another 10 people were slightly wounded," a police officer in Pattani told Reuters.
The insurgents tried to set off bombs or start fires in nine other places in the city from early on Sunday, but the authorities thwarted those attempts.
"There was a tip-off from villagers that male insurgents disguised as Muslim women, with covered faces, had tried to put bombs in several places," another police officer said.
Wednesday's death toll was the highest since security forces stormed the Krue Se mosque in 2004, killing 32 Muslims in a raid that intensified the insurgency.
About 94 percent of the 1.7 million people in the three southernmost provinces are Muslim, the main religion in neighbouring Malaysia. About 80 percent of them speak a Malay dialect, according to a 2010 survey by the Asia Foundation.
The three provinces were part of an independent Malay sultanate until annexed by Thailand in 1909. Muslims in the rubber-rich area mostly oppose the presence of tens of thousands of soldiers backed by armed Buddhist guards.
Five soldiers were killed by suspected insurgents last Sunday and earlier in the month four fruit traders from outside the region were found shot dead with their hands and legs bound.
On Friday, the government decided against imposing a curfew in parts of the south. The military already has wide-ranging powers of search and arrest under an emergency decree.