Police stand guard outside Kauhajoki School of Hospitality in western Finland, where a gunman opened fire Tuesday, killing 10 people before committing suicide. (Antti Aimo-Koivisto/Associated Press)

A 22-year-old gunman who killed 10 people before killing himself Tuesday at a vocational school in Finland left notes saying he hated humankind, police said.

The shooter, who was a student at the school, left two handwritten notes in the dormitory, saying he had planned the attack since 2002 and he hated humanity, police said.

He also wrote that the solution was a Walther 22, referring to the .22-calibre pistol he used in the attack.

He fired on students who were taking an exam and then shot himself in the head, He was taken to hospital, where he died hours later.

The shooting occurred just before 11 a.m. local time at the Kauhajoki School of Hospitality, 290 kilometres northwest of Helsinki.

Finland's Interior Minister Anne Holmlund said the man had been questioned by police on Monday but was released because police had no legal grounds to detain him.

Holmlund said the man was detained briefly because of YouTube postings in which he is shown firing a handgun at what appears to be a shooting range.

She said the man had obtained the licence for the gun in August.

Finnish Prime Minister Matti Vanhanen declared Wednesday as a day of mourning for the victims, with flags to fly at half-mast, and he expressed condolences to their families.

"We have experienced a tragic day," he said.

Reijo Lindroos, chief correspondent for Radio Finland, told CBC News he believed many of the victims were women because the shooting took place in a domestic sciences building.

Dozens of shots fired

Witnesses said the gunman was hooded as he made his way into the school and panic spread as he opened fire.

"Within a short space of time, I heard several dozen rounds of shots. In other words, it was an automatic pistol," school janitor Jukka Forsberg told broadcaster YLE.

"I saw some female students who were wailing and moaning, and one managed to escape out of the back door."

The attacker walked into the school armed with a pistol and what appeared to be explosive devices that were used to start a fire, police spokesman Jari Neulaniemi said. Some of those he killed were burned beyond recognition, Neulaniemi said.

Jussi Muotio, superintendent of the Kauhajoki police, said: "The incident is over now."

Police guard an entrance to Tampere University Hospital in Tampere, western Finland, where a gunman who killed 10 people at a vocational school was brought in. He died later of his self-inflicted gunshot wound. (Hannu Kivimki/Lehtikuva/Associated Press)Finnish tabloid Ilta-Sanomat identified the gunman as Matti Juhani Saari, but police would say only that he was born in 1986 and was a student at the school.

In one of the YouTube videos brought to the attention of police, a young man wearing a leather jacket fires several shots with a handgun in rapid succession, Finnish media reported.

The posting, made five days before Tuesday's shooting, gives its location as Kauhajoki.

The posting includes the message: "Whole life is war and whole life is pain. And you will fight alone in your personal war."

Nearly a year ago, gunman Pekka-Eric Auvinen killed eight people and himself at a school in southern Finland. Police at the time said Auvinen, 18, was bullied and a social outcast.

Auvinen killed six students, a school nurse and the principal before killing himself with a gunshot to the head on Nov. 7, 2007.

Police have said Auvinen left a suicide note for his family and posted videos to YouTube before his attack.

There are 1.6 million firearms in Finland. After the shooting last year, the government pledged to raise the minimum age for buying guns from 15 to 18 but made no promises about making major changes its gun laws.

With files from the Associated Press