BELGRADE, Serbia

Three people were killed and one injured in a school shooting in Bosnia Herzegovina on Wednesday morning.

In the northwestern town of Sanski Most, the school principal and a secretary died along with a teacher after a shooter, alleged to be a former school employee, opened fire on them, according to local reports.

Several people were also wounded.

The gunman, claimed to be a former janitor, used an automatic rifle in the deadly attack.

Another person was reportedly seriously injured in the attack and taken to hospital.

"I can confirm that a firearm was used in the high school, and that three people were killed while one was seriously injured. All other details will be known after the investigation," said Adnan Beganovic, spokesman for the Interior Ministry of the Unsko-Sanski Canton.

He said details of the shooting are not yet known, and that there are numerous police teams on the ground.

The victims have been identified as school Principal Nijaz Halilovic, English teacher Gordana Midzan, and secretary Nisveta Kljunic,

"More information will be known during the day," said Beganovic.

Local reports suggest that the alleged suspect had a dispute with the school management. It said he opened fire at the school's principal and other employees before trying to kill himself.

As Bosnian schools are currently on summer break until Sept. 2, no classes were in session.