HELSINKI -- A suspect, under the age of 18, has been detained on strong suspicion of involvement in Tuesday evening's deadly shooting in the central Swedish city of Uppsala, which left three individuals dead, regional police announced at a press conference on Wednesday.

The shooting took place inside a hair salon near Vaksala Market in downtown Uppsala and the victims were reported to be between 15 and 20 years old.

Police confirmed that the incident is being investigated as a triple homicide. The attack occurred in a public setting with numerous witnesses, as crowds had gathered in the area ahead of the First of May celebrations.

Swedish media outlets have suggested that the attack may be gang-related. While police acknowledged a potential connection to ongoing gang conflicts.

"We are continuing to search for others who may be connected to the crime," a police spokesperson said. "There are several individuals of interest whom we are actively working with."

Authorities have not commented on whether the victims were specifically targeted. However, they are taking steps to prevent further violence or retaliatory actions in the wake of the shooting.

Swedish Minister for Justice Gunnar Strommer condemned the attack, describing it as "a brutal act of violence."

Uppsala City Director Birgitta Pettersson told media that police described the shooting as "an isolated incident." As a result, the First of May festivities will proceed, though "the joy will be muted."

Police have increased their presence throughout the city, including in outlying districts, to ensure public safety.

Uppsala, about 70 km north of the capital Stockholm, is the fourth largest city in the country.