Firefighters walk past ambulances and police cars and a truck parked at a school after a shooting in Kazan, Russia, May 11, 2021. (PHOTO / AP)

MOSCOW - Seven school children were killed on Tuesday and many more wounded after a lone teenage gunman opened fire in a school in the Russian city of Kazan, the head of the region said. 

Two children could be seen leaping from the third floor of the four-storey School Number 175 to escape as gunshots rang out, in a video filmed by an onlooker that was circulated by Russia's RIA news agency.

Calling the attack a big tragedy for the whole country, Rustam Minnikhanov, the head of the wider Tatarstan region, said there was no evidence that anyone else had been involved

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Calling the attack a big tragedy for the whole country, Rustam Minnikhanov, the head of the wider Tatarstan region, said there was no evidence that anyone else had been involved. 

"We have lost seven children...four boys and three girls. And 16 people, 12 children and four adults, are in hospital," Minnikhanov told state TV. "

The terrorist has been arrested. He's a 19-year-old who was officially registered as a gun owner." It was possible the toll would rise. Earlier, Russian news agencies, citing a health ministry source, said 11 people had died. 

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Footage posted on social media showed a young man being pinned to the ground outside the school building by a police officer. Other footage showed emergency service vehicles parked outside the school, with people running towards the building. 

Kazan is the capital of the Muslim-majority region of Tatarstan and located around 725 km east of Moscow. 

School shootings are rare in Russia. One of the last major shootings of its kind took place in Russian-annexed Crimea in 2018 when a student at a college killed 19 people before turning his gun on himself.