Security forces have raided an Islamic school in southern Thailand and said they have detained 60 students and teachers for questioning.

According to Colonel Chamlong Ngamnet, Monday's raid was conducted after a group of suspected separatists opened fire on the motorcade of a high-ranking civil servant in the area.

"We have received information that some might have information about the incident on Saturday and others might have ties to the insurgency," he said, referring to the raid on the Saengtham Wittaya school in Bacho district in Narathiwat province.

He said police found a book about suicide bombings in one of the rooms at the school's dormitory.

"We will release those who are not involved. We just wanted to question them about recent activities at the school and in the area," Chamlong said.

"No one was injured in the raid that was carried out by more than 200 police and soldiers."

The military can search and detain suspects for interrogation for 30 days without charge under a state of emergency that has been in place in the region since July 2005.

More than 3,700 people have been killed in Thailand's three southernmost provinces since a separatist movement began in January 2004.

The provinces - Narathiwat, Pattani and Yala - are the only Muslim-majority areas in the mainly Buddhist country.

Muslims in the area have long complained of discrimination by the central government.

The region used to be an Islamic sultanate until it was annexed by Thailand in the early 20th century.