Seven children and two adults have been killed in a shooting at a school in the Russian city of Kazan, officials say.

Twenty one other people, mostly children, were injured. A 19-year-old suspect was detained.

The attack happened in the capital of the republic of Tatarstan, 820km (510 miles) east of Moscow.

Russian PM Mikhail Mishustin spoke of "great sorrow" while Tatarstan's leader Rustam Minnikhanov described the attack as a "major tragedy".

"We are deeply saddened that this has happened," he said.

Responding to the shooting, Russian President Vladimir Putin said he would review the country's gun control laws.