MOSCOW (AP) — Twenty-three people remain hospitalized following a school shooting in the Russian city of Kazan which killed nine people, including seven youngsters. All 23 were in stable condition Wednesday morning, the authorities said, though at least eight people were to be transferred to Moscow for treatment. A gunman on Tuesday morning launched an attack on a school in Kazan, a city 430 miles (700 kilometers) east of Moscow, sending students hiding under their desks or running out of the building. Nine people — seven students and two school employees — were killed. The 19-year-old attacker has been arrested. Wednesday was declared a day of mourning in Tatarstan, the Russian region of which Kazan is the capital.