The police responding to the attack encountered firing so intense that they struggled to tell how many gunmen were on the scene, an official said.

Officials in Sweden have vowed to determine why a man killed 10 people, and apparently himself, in an unprecedented attack that's shaken their "society to its core."

OREBRO, Sweden - Survivors of Sweden’s worst mass shooting on Feb 5 recalled trying to save the lives of their comrades at a school for adults in Orebro, a day after a gunman killed 11 people on what the prime minister called a “dark day” in the country’s history.