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".

OREBRO, Sweden (Reuters) - Swedish police found three rifles in the adult education centre in Orebro where a gunman killed 11 people and wounded several others this week in the country's deadliest mass shooting, a spokesperson said on Thursday.

Around 10 people were killed in a school shooting in Örebro. The damage at the crime scene was so extensive that investigators were unable to be more definitive, said Roberto Eid Forest, head of the local police.

Police say 10 people have been killed in a shooting at an education centre in central Sweden, including the suspected gunman. Prime Minister Ulf Kristersson described Tuesday's attack at Risbergska school in Orebro, 200km (124 miles) west of the capital city Stockholm, as the "worst mass shooting in Swedish history".

Police remained on the scene of an adult education center in Orebro, Sweden, where a deadly shooting left around 10 people dead on Tuesday, Feb. 4.

Sweden’s prime minister said the attack at the Risbergska School was the worst mass shooting in country’s history

Sweden’s worst mass shooting has left at least 11 people dead including the gunman and five seriously wounded at an adult education center

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