RUSSIA- Moscow Police has revealed that a student who entered a Moscow Secondary School and held more than 20 fellow pupils hostage, has been arrested.

According to the police, the gunman killed one Biology subject teacher and one police officer, while injuring another officer in the process.

It was gathered that the gunman is a pupil at School No. 263 on the northern outskirts of Moscow, while the hostages he held have been released by the police.

"The person who took 20 people and a teacher hostage is a student in the upper classes at the same school," an interior ministry spokesman said on state TV.

"He has been neutralised and all the students have been freed," he said.

"One policeman was fatally wounded during the operation and died in hospital, and a teacher at School No. 263 was also killed," he added.

Reports say the gunman opened fire on police officers who arrived at the scene.