The 4th Army Region has ordered a security cordon to be set up around Watthanatham Islam Phor Ming School in Pattani's Panare district, where a teacher was shot and injured early this week.
Security is being tightened on the order of 4th Army Region commander Pornsak Poolsawat.
Strict surveillance measures have also been put in place in the area following Sunday's attack on Yuso Yala, a religious studies teacher at the school. Security forces have also been instructed to increase the frequency of patrols.
Authorities held drills to prepare for a security emergency at schools and temples, and a protocol was laid out to protect students and teachers in such cases.
Lt Gen Pornsak also told local police to expedite the investigation into Mr Yuso's shooting and quickly apprehend the gunman.
He rejected allegations the shooting was the work of security forces, saying "anyone could have had access to the school's premises".
Tensions flared at the school when security officials brought in Mukta Waloh -- a teacher who is Mr Yuso's brother-in-law -- to the local police station for questioning, after investigators suspected the shooting was motivated by an internal conflict within the school, said Pol Col Seri Sompaiboon, the acting chief of Panare district police.
"As Mr Yuso was still recovering from his injuries and was unable to speak to police, investigators decided to interview someone close to him instead and they asked Mr Mukta to give a statement," he said.
"However, when Mr Mukta learned he was being asked to come in for an interview, he began to yell.
"This caused students at the school who misunderstood the situation to rush out of their class in a bid to defend him."
Officers promptly escorted the teacher out of the school to avoid a confrontation, he said.
Meanwhile, two people were killed and four others injured after a shooting in tambon Bang Roh in Yala's Yaha district yesterday.
The shooting was reported at 6am, prompting Pol Cap Prasopchok Trakoonin, an investigator at Yaha district police station and rangers to rush to the scene.
The two victims -- Thanawut Khemkratok, 38, and Pisit Chaiyasit, 22 -- were out foraging for food in a forest when an unknown number of assailants fired at them.
Mr Thanawut was wounded, but Pisit died at the scene.
The rangers went in to examine the scene and as they did, a bomb planted nearby was detonated killing ranger Noppadol Chukul and injuring three others.