Europe correspondent Mark Stone said the attacker, thought to be in
his 20s, is understood to have been carrying more than one weapon.
The motive for the attack remains unclear.
Four people were earlier said to have been admitted to the nearby NAL hospital in Trollhattan.
The assailant is currently being treated for gunshot wounds, hospital spokesman Niklas Claesson said.
"The other people treated at the hospital are young but not kids," he said.
"Some of them have serious injuries and are being operated on.
"One person is deceased at the scene," the spokesman added.
Some 400 students, ranging from pre-school to high school, attend the school.
More follows..
