[Source: Reuters]

Several shots were fired outside a school in Oslo  and three suspects have since been apprehended, Norwegian police said.

Investigators believed one person may have been injured in the shooting but the victim had not been located, police spokesperson Anders Roenning told Norwegian daily VG.

Several bullet casings were found at the scene, he added.

Linderud School in north-east Oslo has about 480 students from first to tenth grade and a staff of around 100, according to its website.