The suspect, a school employee, opened fire with an automatic rifle and tried to kill himself, police say.
At least three staff members have been killed in a shooting at a school in the northwest of Bosnia and Herzegovina, authorities say.
Among those killed in Wednesday’s shooting were the principal, secretary and a teacher at the Sanski Most High School Center, Adnan Beganovic, a spokesman for the Ministry of Internal Affairs, told Al Jazeera.
The shooting took place at 10:15am (08:15 GMT). The Reuters news agency reported quoting police that a school employee was involved in the shooting.
The Sanski Most town is located approximately 200km (124 miles) northwest of the capital, Sarajevo.
Schools in Bosnia are closed for the summer holiday, which means no classes were being held at the time of the shooting. While no students were present, teachers were meeting to prepare for the upcoming school year.
The suspect “used a military firearm, an automatic rifle, to kill three school employees and tried to kill himself”, Beganovic told national radio.
The wounded man was reported to be in serious condition and was taken to Banja Luka Hospital.
The employee allegedly had a dispute with the school management, The Associated Press news agency said. Police are yet to provide a motive for the attack.
Police and emergency services were deployed to the site.
The Balkan region has been awash with small arms and weapons since the wars of the 1990s, which saw Yugoslavia break up, particularly in Bosnia, a country of about 3.5 million people. But mass shootings are rare.
According to a 2010 study by the United Nations Development Programme (UNDP), there were about 750,000 weapons in illegal possession in Bosnia.
The last school shooting in the Balkans took place in May 2023 in Belgrade, Serbia, when a teenager shot dead 10 people, including nine classmates.