When the ambulance arrived the woman was unconscious and she was rushed to hospital by helicopter.
“The man has been arrested for attempted murder and the area has been cordoned off,” said Björn Engström at Stockholm police to news agency TT on Monday morning.
The woman was taken to Karolinska University Hospital where her condition was initially described as “serious and life-threatening”.
The man was also taken to hospital for examination.
“Not because he is injured but due to technical reasons – to try to understand what has happened,” Anders Olsson said.