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.”

Swedish police said the gunman in the country’s worst mass shooting was connected to the adult education center where he opened fire Tuesday, killing 10 other people. Police later found him dead.

Swedish police confirm around 10 people were killed at a school for adults on the outskirts of Stockholm. The gunman is believed to be among the dead.