Five people, including two policemen, were killed in a bombing and separate shooting attacks early Friday in the violence-plagued south of Thailand.
A mobile phone-triggered device apparently targeted a unit of four police officers who were doing a security inspection to prepare a safe passage for teachers as they went to school, said police Col. Term Intarasara.
Two police died at the scene, and another was critically injured, while the fourth suffered minor injuries.
The bomb exploded about two kilometers (a mile) from the school in Sungai Padi district of Narathiwat.
"The police were on foot clearing a path before allowing teachers to go through, and the bomb planted on the roadside exploded," Term said.
The explosion came two days after two marines were held hostage also in Narathiwat and killed by villagers who had blamed them for an earlier shooting incident.
More than 3,000 police and military have been assigned to provide security for teachers in Thailand's three troubled Muslim-dominated provinces after a number of teachers were killed by suspected Muslim insurgents. These security patrols have frequently been targeted by roadside bomb attacks.
In a separate attack later also in Sungai Padi, three soldiers were injured when a remote-controlled bomb buried on the roadside exploded as the soldiers' car passed in a village, police said.
Also Friday, suspected insurgents fatally shot a Myanmar migrant construction worker in Yala province, said police Col. Chaithat Intarachid. In separate attacks in neighboring Pattani province, suspected insurgents shot and killed a Thai construction worker and a public health office employee, said police Lt. Col. Chatchai Bumrungkorn.
The three southernmost provinces, the only ones with Muslim majorities in the Buddhist-dominated country, have been wracked by an Islamic separatist insurgency in which more than 1,000 people have died since January last year.