A 12-year-old suspected of shooting dead another boy of the same age at his school said he had been motivated by bullying, Finnish police said on Wednesday.

Two girls were wounded on Tuesday morning in the shooting at the Viertola school in the city of Vantaa, which is located immediately north of the capital, Helsinki.

Flags flew at half mast across the country on Wednesday.

What do we know about the shooting in Vantaa?

A preliminary police probe had confirmed that the suspect had been a target of bullying, investigators said in a statement.

During a Wednesday press conference, municipal officials did not comment on whether the school was aware of the bullying.

Police have not yet commented on whether the suspect sought to target specific individuals.

The revolver used in the shooting was registered to a relative of the suspect, according to police. Officers said this was being investigated as a separate firearms offense.

Police have opened an investigation into murder and attempted murder. The suspect cannot be held in police custody because of his age and has been handed over to social services.

Suspect threatened other students before shooting

Investigations had shown that the suspect threatened other students on their way to school in a northern neighborhood of Helsinki.

"The suspect had threatened them with a gun when leaving the Viertola school after the shooting," police said.

The Finnish broadcaster MTV Uutiset reported that the boy wore a mask and noise-canceling headphones when he carried out the shooting.

The two girls injured in the attack remained in hospital as of Wednesday.

Following school shootings in 2007 and 2008, Finland increased the minimum age for gun ownership and gave the police more powers to check people applying for licenses.

The Finnish Interior Ministry says that there are more than 1.5 million licensed firearms in Finland and around 430,000 authorized owners.

sdi/lo (AFP, dpa, Reuters)