Some 30 people were involved in the street fight in Skarpnäcks Gård, a suburb in southern Stockholm around 2.30pm on Saturday, witnesses told police.
“Everyone seems to have fought against everyone, and a lot of people say cudgels were used”, said information officer Eva Nilsson, speaking to the TT newswire.
Witnesses quoted by Swedish tabloid Aftonbladet said batons were used, and a driver deliberately hit someone with a car.
Four people were taken to hospital, bleeding but without life-threatening injuries. At around 4pm, police were still questioning people in order to find out what happened.
At the time, the reason behind the fight was still unknown.
However, a man who lives in the area and was passing by as the fight started, told Aftonbladet: “They were hitting each other and cars, and then they hit someone with a car. It is terrible. Let's hope it was a one-off.”