Religious leaders joined security authorities in condemnation of the fatal ambush of a family taking their children to school in a pickup truck in Narathiwat, denouncing the gunmen as "misfits", "cowards" and "barbarians".
Four people were killed - the driver, an 8-year-old boy and two women - in the ambush in Rueso district on Thursday morning. The boy was one two sons that Somchai Thongjan, his wife and sister-in-law were taking to school.
The second son, a 12-year-old, was seriously wounded and rushed to hospital by rescue units. A 6-year-old niece also in the vehicle received scratches and cuts.
"What the insurgents did clearly shows that they are cowards. They acted like barbarians," Col Pramote Prom-in, a spokesman for the Internal Security Operations Command's southern office, said.
Children and women should not be targetted, he added.
Somchai was an assistant village chief of Ban Sri Pinya. He was driving the two boys to school, before heading to the district town, where he was to attend a meeting.
Nimu Makaje, a former deputy Islamic leader in Yala, and Panu Uthairat, the former secretary-general of the Southern Border Provinces Administrative Centre, and Prime Minister Prayut Chan-o-cha all expressed their shock at the attack and offered condolences to the family.
Mr Nimu said the gunmen were trying to derail attempts to restore peace in the southern provinces and deepen the religious schism in the region.
The attack occured soon after the government and Mara Patani, an umbrella of insurgent groups, agreed to create safety zones in the provinces. The two sides are in talks to end militant attacks in the border area.
Gen Prayut called for better measures to ensure the safety of teachers, students and temples. He admitted it was not possible for security forces to cover all roads in the border region.