About 10 people including the gunman have been killed at an adult education center in what Sweden’s prime minister called the country’s “worst mass shooting.”

Police said “around 10 people” were killed at a school on Tuesday, in what has been described as the worst mass shooting in Sweden’s history. The suspected perpetrator is among the dead.

The Orebro Police spokesperson confirmed that a major operation is underway at a school in Västhaga in Örebro and four people have been shot in the shooting.