The note, which was handed in to the office by a group of female students, contained “unknown threats” and made reference to “possible explosive devices” on the grounds of Gladstone State High School, Sergeant Wayne Butcher said.

“It was a disconcerting note and they took it straight to the office,” Sgt Butcher told The Observer.

The bomb squad was called to the scene and students were led to the school oval, then later taken to a safe location.

Officers are talking to a large group of students at the school’s front gates, by the main entrance on the Dawson Hwy.

A fire truck is also parked at the scene.

Nearby Toolooa State High School was evacuated in response to a bomb threat on Tuesday.

A statement released by the school from its acting principal Bryan Townsend said students and teachers returned to classrooms after the threat about 2.30pm to collect their school bags and gathered at the shelter at 2.45pm for a debrief.

“I want to reassure you that we treat the safety and welfare of your children, our students, as our highest priority at all times,” Mr Townsend said.

“I would like to thank our staff and students for promptly carrying out the evacuation.”