TUUSULA, Finland (AFP) - A shell-shocked Finland was in mourning Thursday after a teenaged gunman massacred eight people at a school in what he claimed was an attack on "humanity".

Flags flew at half mast across the Nordic country a day after 18-year-old Pekka-Eric Auvinen went on his shooting spree at Jokela High School in Tuusula -- a small, picturesque town of just 30,000 inhabitants on the banks of a lake north of Helsinki.

Auvinen had advertised his intentions by posting a notice detailing how he would carry out the massacre on file-sharing website YouTube before the attack.

"I don't want this to be called only as 'school shooting'," he said of the massacre, which appears to have been planned to coincide with the anniversary of the Bolshevik revolution.

Flowers, wreaths and burning candles were laid out around the grounds of the school Thursday in remembrance of the victims -- the school's headmistress, nurse and six students.

Police and army conscripts blocked all access to the school, which counts around 450 middle and secondary school students and will remain closed at least until the end of the week.

"Tuusula will have lifelong scars," mayor Hannu Joensivu told the FNB news agency.

Auvinen ended the rampage by shooting himself with his weapon, a 9mm handgun he had nicknamed "Catherine" and for which he only received a license last month. He died of his injuries late Wednesday.

The 18-year-old, described as an adherent of extreme philosophies on both the left and the right, seems to have planned his attack in minute detail and intentionally staged it on November 7, the 90th anniversary of the Bolshevik revolution in Russia.

In the "attack information" notice he posted on YouTube, he clearly detailed his intentions.

"Target: Jokela High School, students and faculty, society, humanity, human race ... Attack type: mass murder, political terrorism."

"Although I choosed (sic) the school as target, my motives for the attack are political and much much deeper and therefore I don't want this to be called only as 'school shooting'," he added in the message which was rapidly removed from the sight after attack.

Tero Haapala of the Finnish national police said Thursday it appeared Auvinen had picked his victims at random and had been trying to kill as many people as possible.

"There is every indication that if he was going to do something it had to be something big," he told the FNB news agency.

The twelve people injured in the attack, most of them suffering cuts from broken window panes as they frantically jumped out of school windows to escape the rain of bullets, had been released from hospital.

Police have said Auvinen, a broad-shouldered youth with blond slicked-back hair, came from a "normal" family, living with both parents and a brother, and had no previous criminal history.

Several of the 18-year-old's classmates and teachers however described a brilliant but complex loner obsessed with weapons, Internet war games and revolutionary history who was often bullied and tormented.

According to some students, the perpetrator of one of the worst tragedies in recent Finnish history had been taking anti-depressant medications and had made no secret of his admiration for Hitler and Stalin.

The shooting sent shockwaves through Finland, which with its mere 5.4 million inhabitants and low crime rates, is unaccustomed to such violence.

Finnish Prime Minister Matti Vanhanen described the shooting, the worst in the Nordic country's history, as "a great tragedy."

"This is an awful day ... The shooting has deeply undermined the sense of security in society ... Nobody had expected such things," Vanhanen said

Grief and disbelief in Finland after school massacre - Yahoo! News