Sweden’s worst mass shooting left at least 11 people dead, including the gunman, yesterday.

The gunman’s motive, as well as the number of wounded, had not been determined by early Wednesday as Sweden — where gun violence at schools is very rare — reeled from an with such bloodshed that police early on said it was difficult to count the number of dead among the carnage.

The school, called Campus Risbergska, offers primary and secondary educational classes for adults age 20 and older, Swedish-language classes for immigrants, vocational training and programs for people with intellectual disabilities. It is on the outskirts of Orebro, which is about 125 miles west of Stockholm.

Footage showed people fleeing the campus on Tuesday while gunshots could be heard. Justice Minister Gunnar Strömmer called the shooting “an event that shakes our entire society to its core.”

Here is everything we know so far about the tragedy:

The shooting started Tuesday afternoon after many students had gone home following a national exam. Students sheltered in nearby buildings, and other parts of the school were evacuated following the shooting.

Teacher Lena Warenmark told SVT News that there were unusually few students on the campus Tuesday afternoon because many went home after a national test. She also told the broadcaster that she heard probably 10 gunshots. A video from the scene showed a large police presence and other emergency vehicles. Students were sheltering in nearby buildings. Other parts of the school were evacuated following the shooting, which began at around 12:30 pm local time (1130 GMT).

Andreas Sundling, 28, was among those forced to barricade themselves inside the school. “We heard three bangs and loud screams,” he told Expressen newspaper while sheltering in a classroom. “Now we’re sitting here waiting to be evacuated from the school. The information we have received is that we should sit and wait.”

Prime Minister Ulf Kristersson told reporters in Stockholm late Tuesday: “Today, we have witnessed brutal, deadly violence against completely innocent people. This is the worst mass shooting in Swedish history. Many questions remain unanswered, and I cannot provide those answers either.

“But the time will come when we will know what happened, how it could occur, and what motives may have been behind it. Let us not speculate." While gun violence at schools is very rare in Sweden, people were wounded or killed with other weapons such as knives or axes in several incidents in recent years.

Authorities are working to identify the deceased, and police said the toll could rise. Roberto Eid Forest, head of the local police, told reporters the suspected gunman was among the dead. So far police said 11 people had died, including the suspected gunman, and it is unclear about the number of injured. Officials said all of those who died were found inside the school building.

While is also still not clear how many people were wounded, Sweden's justice minister said there were "many others injured". And the picture was not very clear in the first few hours after the attack with many different reported figures.

Despite media reports of deaths and many hurt, police first gave an official briefing at 3.30pm local time when they said only that five people had been injured. Swedish media continued to report that several people had died, before police confirmed in an update at 11.55pm that at least 11 people were dead.

There were no warnings beforehand, and police believe the perpetrator acted alone. Police have not said if the man was a student at the school. They haven’t released a possible motive, but authorities said there were no suspected connections to terrorism at this point.

Police raided the suspect’s home after Tuesday’s shooting, but it wasn’t immediately clear what they found. "We're working with secret services but as far as I know, it's a person unknown to police," said Roberto Eid Forest, Orebro's local police chief, when asked if the perpetrator lived in Orebro.

Forest added that he couldn't say anything about the kind of weapon that was used "other than it was a firearm". Asked about reports the gunman shot himself, police said they did not have any information about that.

So far no names have been given by the police on the victims who say they are still trying to identify them and notify their relatives. They have invited families to an event at 10am local time on Wednesday, where they will update them on what is known so far.

But the school where it happened provided municipal adult education for people aged over 20 who did not finish primary or secondary school. Teachers have said there were unusually few students at the school on Tuesday as many had gone home for the day after sitting a national exam.