A Thai military spokesman said a roadside bomb in insurgency-plagued southern Thailand killed three policemen and wounded one other on Thursday.
The military spokesman said the police officers were returning to their base after they had escorted teachers to school when the 15-kilogram bomb went off in Pattani, one of three southernmost provinces where an Islamist insurgency has been going on since early 2004.
Local television pictures showed wounded policeman being rushed into hospital for treatment.
School teachers are usually escorted to work and back by the security forces.
Police said the militants believed the government was trying to indoctrinate students with un-Islamic values at state schools, making teachers prime targets of the violence.
No one was arrested or claimed responsibility for the attack.
APTN