The bomb was hidden in a pickup truck that was parked in front of a karaoke bar in a commercial district in Narathiwat province, police Col Manit Yimsaai said. He said the explosion wounded two soldiers and 11 civilians, one of them seriously.
Manit said the blast just after the lunch break also damaged rows of restaurants and shops in the predominantly Buddhist neighbourhood.
He said the pickup was reported to have been stolen on Thailand's southern border with Malaysia and had been used in a previous rebel attack.
Suspected militants also threw a pipe bomb at a restaurant 50 meters (yards) from the first explosion, but the improvised device did not go off and was defused, police said.
Manit said an explosive ordnance disposal unit used water canon to successfully destroy another explosive device hidden in a motorcycle in front of a nearby grocery store.
Narathiwat is one of the three Muslim-majority southern provinces in Buddhist-dominated Thailand.
More than 5,000 people have been killed in the region since an Islamic insurgency erupted in 2004.

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