Three people have been killed and two soldiers injured in separate incidents across Thailand's insurgency-hit south, as the army warned Wednesday of an escalation in separatist attacks. Two privates assigned to protect teachers in the Muslim-majority southern province of Yala were seriously wounded in a roadside blast early Wednesday, officials said. A 46-year-old school bus driver was later killed in a drive-by shooting by suspected rebels in Pattani province, police said, while an unidentified man was shot dead by security forces at a check-point.