Oslo police shot the suspect 15 minutes after the vehicle was taken.
An armed man stole an ambulance and ploughed into a family on an Oslo street on Tuesday, putting two seven month-old twins in hospital and injuring three other people.
In a statement on Twitter, Oslo police said that the ambulance was stolen at around 12.30 local time after a crew was called to the scene of a traffic accident.
The hospital was able to track the stolen vehicle, which was halted after another ambulance drove into it. Police on the scene then opened fire on the vehicle, arresting the driver at 12.45 pm.
Although the suspect was shot at during the arrest, he was not critically injured, police said. The incident happened in the Torshov neighbourhood of Oslo.
"An armed man stole an ambulance, drove away and hit some people. We got him now," the police spokesman said.
"Two babies were injured after the hijacked ambulance hit a family. They are twins, seven months old, they are being treated," an Oslo University hospital spokesman said.
Police said the suspect appeared to deliberately hit pedestrians and that they had found a significant amount of "drugs" following the arrest, as well as a shotgun and an Uzi automatic weapon.
Authorities have opened an investigation into whether the suspect had ties to far-right extremists, though a motive has not yet been established and the suspect still needs to be interviewed.
"There is nothing to indicate that this incident is terrorism related," Oslo police operations leader Erik Hestvik told reporters. The police added in a statement: "The investigation is still in an early phase ... We are conducting a broad, intensive investigation."