A 12-year-old student opened fire at a secondary school in southern Finland and wounded three students on Tuesday, police said.

The suspect was later arrested, police said.

Heavily armed police cordoned off the lower secondary school, with around 800 students, in the city of Vantaa, just outside the capital, Helsinki, after receiving a call about a shooting incident at 9.08am.

Police said the wounded were also aged 12.

Police said the suspect was arrested in the Helsinki area later Tuesday.