There was blood everywhere,” 16-year-old Linn told reporters at the scene of what has been described by Sweden’s prime minister as the worst mass shooting in the country’s history.
Eleven people died after Tuesday’s attack at an adult education centre in the city of Orebro, including the suspected gunman. Police say the number of injured remains unclear.
Linn, who goes to a different school near the site, told AFP news agency “it was chaos”, with people panicking and crying.
What is also not yet known is the motive for the attack, but police have said “everything indicates” that it was not ideological.
Prime Minister Ulf Kristersson said it was difficult to grasp the magnitude of what happened. Flags on government buildings, parliament and the royal palaces will fly at half-mast on Wednesday, the prime minister’s press office said.
A student at the Risbergska school recalled how she and others tried to help one of the victims.
“A guy next to me was shot in the shoulder. He was bleeding a lot. When I looked behind me, I saw three people on the floor bleeding,” Marwa, who only gave her first name, told TV4 Sweden.
Marwa said she and another friend tried to help the injured person by wrapping a shawl around the man’s shoulder “so that he wouldn’t bleed so much”.
“Everyone was so shocked.”
Teacher Lena Warenmark recalled hearing around 10 gunshots close to her study, telling Swedish public radio that she heard a few bangs in short succession, followed by a short pause, and then a few more.
Ms Warenmark said she was confined to her study for over an hour.
Police said they heard reports of a shooting at an adult education centre in Orebro, 200km (124 miles) west of the capital city Stockholm, at 12:33 local time (11:33 GMT).
The facility sits on a campus home to other schools. These centres are attended primarily by people who have not finished primary or secondary school.
Police earlier warned the death toll could rise as several people had been injured.
Hellen Werme, also a student at the Risbergska school, was at the site when the shooting took place. Her teacher shouted at her and her peers, urging them to close the doors and lie down on the floor, she told Sweden’s public broadcaster SVT.
Ms Werme said the wait was terrible and her main worry was whether she would be able to come home to her children.
Ali el Mokad, a relative of a man who is believed to have been studying at the school at the time of the attack, had positioned himself outside a local hospital waiting to hear on his relatives’ condition.
“It doesn’t feel very good actually,” Mr Mokad told Reuters news agency. He said his cousin also knew someone at the school, and when she called her friend earlier, “she fell to the ground because she was crying so much”.
“She thought what she saw was so terrible. She only saw people lying on the floor, injured and blood everywhere,” Mr Mokad said, describing the scene his cousin’s friend had witnessed.
Such attacks are very rare in Sweden. While there have been school shootings in Sweden before, they have not been of this magnitude.
Last September, there was a school shooting south of Stockholm, when a 15-year-old is suspected to have wounded a classmate – although that attack was linked to Sweden’s problem of gang violence.