According to information to Expressen, a person in his 30s has been arrested.
The person must have been taken to hospital by ambulance, according to one of SVT's team located on Gotland.
- I am shocked, says a witness who SVT Nyheter has spoken to.
A street and a piece of the square have been blocked off.
The police's spokesperson, Ola Österling, tells SVT that this is a violent crime.
The police are now working to collect witness information on the spot.
The victim's injury status is currently unknown.
Annie Lööf's press conference is moved forward
At 2 pm, the Center Party's Annie Lööf would have held a press conference, but due to the ongoing police operation in Visby, the press conference has been moved forward.
The text is updated.