The police say that the man is "critically injured, but reportedly stable."
The alarm about loud bangs was received by police at 1:30 p.m. on Wednesday.
An injured man was found in a stairwell at the scene. He was reportedly conscious when taken to hospital.
Two people were arrested shortly afterwards. They are suspected of attempted murder and aggravated weapons offenses.
"It concerns a man in his mid-30s and a man in his 20s," says Fredrik Svedemyr, press spokesperson for the police.
Police are continuing their investigation at the scene.
