Survivors of Sweden's worst mass shooting on Wednesday recalled trying to save the lives of their comrades at a school for adults in Örebro, a day after a gunman killed 11 people on what the prime minister called a "dark day" in the country's history.

The king and queen visited the scene of the tragic event that occurred on Tuesday and Swedish flags were flown at half-mast to honor the victims.

Swedish police are still investigating the gunman's personal history and have not said the attack, which killed 11 people, was targeted. Hellen Werme, a 35-year-old trainee nurse, survived the shooting. She and her classmates locked themselves inside their classroom as the shooter prowled the corridors.