At least 10 people, including the gunman, were killed Tuesday at an adult education center in what Sweden’s prime minister called the country’s worst mass

Police said they do not know the motive but do not believe it is terrorism, adding they "had no warning sign" about the attack. Officers are working to identify the perpetrator and the victims.

Around ten people have been killed in a shooting at an adult school campus in central Sweden on Tuesday afternoon, police said. The shooting that took place at Risbergska School in Örebro, 125 miles west of Stockholm, is the worst mass shooting in the country's history, the prime minister Ulf Kristersson said.