A gunman who killed 11 people, including himself, at an adult education centre in central Sweden may have been a student at the school, police said on Thursday, as they described chaotic scenes after the country's deadliest mass shooting as being like an "inferno".

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.

Badly wounded, Salim Karim Iskef managed to video-call his fiancée to say he loved her one last time before he died in Sweden's deadliest mass shooting.

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.

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.

Sweden is reeling from the country's deadliest mass shooting this week as investigators continue to look into the gunman's motive.

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

Police confirm seven women and three men - aged between 28 and 68 - were killed in the country's worst mass shooting.