HELSINKI, Finland (CNN) -- An 18-year-old gunman opened fire at a school in Finland killing a headteacher Wednesday, in a shooting that appeared to have been planned out in graphic videos posted on Internet sharing site YouTube.
The incident, believed to be the first of its kind in Finland's history, was claimed to be the work of Pekka-Eric Auvinen, who has also published a manifesto demanding war on the "weak-minded masses" and pledging to die for his cause.
YouTube suspended the videos, many of them featuring Nazi imagery, shortly after police in the town of Tuusula, near Helsinki, were reported to have apprehended the gunman.
One video posted by a user identified as "Sturmgeist89" earlier Wednesday was was titled "Jokela High School Massacre - 11/7/2007."
The school involved in the shooting was reported to be Jokela High, attended by more than 400 students, aged between 12 and 18.
Jarkko Sipila, a reporter with MTV, told CNN that the shooting happened around noon Finnish time (1000 GMT) in the quiet town around 50 kilometers (30 miles) north of Helsinki.
Sipila said some of the pupils had fled to a nearby elementary school while police surrounded and sealed off the high school. Finnish news agency STT carried police comments that they had been fired at.
The Associated Press reported comments from Kim Kiuru, one of the school's teachers, on radio station YLE.
Kiuru described how the headmistress used the public address system around noon to tell pupils to stay in classrooms.
He said he locked his classroom door, then waited in the corridor for more news.
"After that I saw the gunman running with what appeared to be a small-caliber handgun in his hand through the doors towards me, after which I escaped to the corridor downstairs and ran in the opposite direction, " Kiuru said.
The agency reported Kiuru as saying that he saw a woman's body as he fled the school, before telling his pupils to leave the building through the windows.
Sipila said that at least four people in the school had suffered gunshot wounds and that others had been injured by shattered glass.
He added that the gunman, believed to be an 18-year-old 12th grader, is thought to have had a fascination with dictatorial figures such as Hitler and Stalin.
Sipila said that Finland has around two million firearms, although gun laws are tough. "We do not know where he got it from," he said.
Police are scheduled to give a press conference at around 1500GMT.
