A shooting at an adult education centre in Sweden on Tuesday left five people wounded, a figure that apparently includes the gunman, officials said. One of the wounded was in serious condition.

Few other concrete details emerged from a news conference that included police and medical officials hours after the shooting on the outskirts of the city of Orebro, which is located about 200 km west of Stockholm.

The local head of police, Roberto Eid Forest, told reporters that investigators were working to determine more information about the shooting.

“The investigation is somewhat unclear,” he said during the briefing. “It is unclear whether the shooting took place inside the school (building) or whether there may be more perpetrators.”

Gun violence at schools is very rare in Sweden. But there have been several incidents in recent years in which people were wounded or killed with other weapons such as knives or axes.

The police would only say that the gunman was one of the people hospitalised after Tuesday's shooting. Four of the five people who were shot underwent surgery, including one person who was seriously wounded. Two others were described as stable and another was considered slightly injured, Jonas Claesson, regional director of health and medical services, said during the news conference. The police said that no officers were shot.

The school, called Campus Risbergska, serves students who are over age 20, according to its website. Primary and upper secondary school courses are offered, as well as Swedish classes for immigrants, vocational training and programmes for people with intellectual disabilities.

The shooting erupted after many students had gone home following a national exam. Police vehicles and ambulances, lights flashing, blanketed the parking lots and streets around the school as a helicopter buzzed overhead.