A schoolboy opened fire on students and security guards in a Belgrade school on Wednesday, Serbian police said, adding that they had arrested a suspect.

Several shots were fired and several people were wounded, police said in a statement, without specifying how many. The suspect is a seventh grade student.

Casualties are being treated and an investigation into the motives behind shooting is under way, police said, without elaborating. (Reporting by Aleksandar Vasovic; editing by John Stonestreet)