MOSCOW (AP) — More than a dozen people wounded in a school shooting in central Russia will be medevaced to Moscow for further treatment, authorities said Tuesday, a day after a gunman killed 17 people and wounded 24 others.

Health Minister Mikhail Murashko said that a medical evacuation is planned for 15 of the injured, including 13 children and two adults. He said three of them are in critical condition.

The shooting in Monday took place in School No. 88 in Izhevsk, a city 960 kilometers (600 miles) east of Moscow in the Udmurtia region, and was one of the deadliest school shootings in Russia. The gunman, a 34-year-old graduate of the school, killed himself after the shooting.

School shootings aren't common in Russia, but have become more frequent in recent years.

A shooter killed six people in a university in Perm a year ago. Just months before that, a gunman opened fire at a school in the city of Kazan, killing seven students and two teachers with a registered weapon. A student at a college in the Russia-annexed Crimean Peninsula killed 20 students and himself in 2018.

Russian authorities last year sought to tighten gun regulations in the wake of the shootings.

Russia’s Investigative Committee identified the gunman in Izhevsk as Artyom Kazantsev and said he was wearing a black T-shirt bearing “Nazi symbols.” No details about his motives have been released, and an investigation is underway. But local officials said he was registered as a patient at a psychiatric facility.

The government of Udmurtia said 17 people, including 11 children, were killed in the shooting. According to Russia’s Investigative Committee, 24 other people, including 22 children, were wounded in the attack.

Kremlin spokesman Dmitry Peskov described the shooting as “a terrorist act” and said President Vladimir Putin has given all the necessary orders to the relevant authorities.

The school educates children between the first and 11th grades.

Russia’s National Guard said Kazantsev used two nonlethal handguns adapted to fire real bullets. The guns weren't registered with the authorities.

Izhevsk, a city of 640,000, is located west of the Ural mountains in central Russia.