Flags have been lowered to half-mast throughout Finland following a tragic incident where a child was killed and two others were gravely injured in a school shooting on Tuesday.

The shooting occurred within a classroom at Viertola school in Vantaa, situated north of Helsinki, the capital.

Authorities confirmed that all three victims were 12 years old, and the suspected perpetrator, also 12, initially fled the scene but was subsequently apprehended.

According to the foreign ministry of Kosovo, one of the wounded children is of Kosovan nationality.

In observance of a day of mourning, all public buildings commenced lowering their flags from 8:00 (05:00 GMT) on Wednesday, as announced by the interior ministry.

Reportedly, the assailant wore a mask and noise-cancelling headphones during the shooting, and he fled upon the arrival of law enforcement. He was later arrested "peacefully" in the northern Siltamaki neighborhood of Helsinki.

An investigation into charges of murder and attempted murder has been launched by the police.

There has been no official update provided on the condition of the injured children.

In a statement on Wednesday, police said they are looking into a possible motive but will not yet be releasing details to the public yet.

"There is a lot of different, and partly incorrect, information about what happened in the different channels of social media. The police still want to remind you that spreading incorrect information on social media is a crime," it said.

Children under the age of 15 are not criminally liable in Finland, so the suspect has not been remanded in custody and will be placed in the care of social services after further questioning.

The suspect is understood to have used a gun licensed to a close relative. Gun ownership is widespread in Finland and children over 15 can have licences to use other people's firearms.

Elina Pekkarinen, Finland's Children's Rights Ombudsman, told Finnish news agency STT, that "for years (we have been repeating) that we need to take violence between children in society seriously".

Acts of violence, particularly amongst children under 15 years old, have been on the rise for several years, she added.

Finland is widely known as a country of hunters and gun enthusiasts and has 430,000 licensed gun owners in a population of 5.6 million, according to government statistics. There is no limit to the number of guns that can be owned and the interior ministry says more than 1.5 million are in circulation.

So sad