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."

Sweden's right-wing government said on Friday it would seek to tighten gun laws in the wake of the country's deadliest mass shooting at an adult education centre where the attacker appeared to have used several of his own licensed rifles.

One day after the killings at an adult educational center, some gathered to lay flowers and come to grips with the violence.