Eight students and a teacher were killed in a school shooting in the Russian city of Kazan, a source in the emergencies services told Russian state media on Tuesday.
At least 32 people who were injured have been taken to hospitals, another source, in the education ministry of the Republic of Tatarstan, told the Tass agency. Kazan is the capital of the republic.
Soon after the shooting, Russian President Vladimir Putin ordered officials to tighten the control of civilian weapons, Kremlin spokesman Dmitry Peskov said.
"The president gave an order to urgently work out a new provision concerning the types of weapons that can be in civilian hands," Peskov said.
Putin expressed his deep condolences to the relatives of the children killed in the armed attack.
Russia's state RIA Novosti news agency reported earlier that 11 people had been killed in the shooting. There was no way to immediately reconcile the differing death tolls.
It was possible the toll would still rise. Six children were in grave condition, RIA said.
Rustam Minnikhanov, president of Tatarstan, had earlier said four boys and three girls died. All were eighth grade students at high school No 175.
"The terrorist has been arrested, (he is) 19 years old. A firearm is registered in his name. Other accomplices haven't been established," Minnikhanov said after visiting the school.
There were also conflicting reports about the attack, with some Russian news agencies reporting two gunmen were involved and others saying one was involved.
All educational institutions in Tatarstan will be inspected, and classes will be canceled in all schools in Kazan on Wednesday, according to Minnikhanov's press office.
A video clip released on social media showed two children escaped the shooting by jumping from the windows on the building's third floor. One video on social media captured a teenager lying on the ground apparently being detained.
Explosion and gunshots
"I was in class, I first heard an explosion, then gunshots," Tass quoted a teacher as saying.
Another sources quoted by the RIA Novosti agency said they heard an explosion and could see smoke rising from the building.
Kazan is located 820 kilometers east of Moscow. Tatarstan authorities have opened a criminal investigation into the shooting.
Russia has relatively few school shootings due to normally tight security in education facilities and the difficulty of buying firearms legally.
Xinhua and agencies contributed to this story.