A gunman opened fire at an adult education center in the Swedish city of Örebro on Tuesday, killing at least 10 people in what the country’s prime minister called the “worst mass shooting in Swedish history.

The shooter targeted a center that serves migrants seeking to integrate into a country that had already reversed its liberal migration policies.

Sweden is set to tighten its gun laws, including a ban on certain semiautomatic weapons, after a mass shooting that left 11 people dead.