Russian state news agencies say a gunman opened fire in a kindergarten in the nation’s western Ulyanovsk region, killing two students and a teacher before killing himself.

The Tass news agency, citing a regional law enforcement official, said the attack occurred in the village of Veshkayma. They said the gunman burst in during “quiet time,” when the children were sleeping. From his Telegram account, regional State Duma deputy Sergei Morozov said the two children were 5 and 6 years old.

The regional Ministry of Health said another kindergarten employee was wounded in the hand and was being treated. The law enforcement officials suggest a domestic conflict may have been the motive for the shooting. They said the identity of the attacker has been difficult to establish.

Rosgvardia, Russia’s national guard, said the shooter was not the owner of the weapon and the rightful owner of the gun had obtained it legally.

Tass reported regional that Governor Aleksey Russkikh is flying to the site of the shooting and has ordered regional officials to provide emergency assistance to the families of the victims.

Some information for this report was provided by The Associated Press and Reuters.