The police received several calls at 22:30 p.m. that someone had shot into a terraced house.
"Three bullet holes were found next to the front door. They may have gone through a window next to or on the door, says Ola Österling, press spokesperson at the Stockholm police.
A man inside the house was hit in the incident and had to be taken by ambulance to hospital.
"He was awake and was able to talk to us on the spot. We assess that he has serious, but not life-threatening injuries, says Österling.
An extensive police operation is underway and the area around the townhouse is cordoned off.
"We are questioning the people who were in the apartment. No one is currently in custody, says the press spokesperson.
"We assume that the incident is linked to criminal networks," he adds.