An armed man opened fire in a pre-school in Russia's central Ulyanovsk region, leaving at least four people dead, local authorities said.
"According to preliminary information there was a shooting in a kindergarten. As a result, two children, a teacher and the attacker died," the head of the Ulyanovsk region information department, Dmitry Kamal, told AFP.
He said investigators were working at the scene to establish further information.
The ages of the dead children were not known, but they would be between three and six years old, Mr Kamal said.
A source in law enforcement told news agency TASS that the shooting may have been the result of a "domestic conflict".
According to Telegram channel Baza - which is known to have sources in Russian law enforcement - the man walked into the kindergarten during nap time with an Izh-27 double-barrelled shotgun. There was no guard on duty.
A former governor of the region said a young teacher was killed and another injured in the attack, while the two killed children were born in 2016 and 2018, RIA Novosti news agency reported.
The gunman is reported to have then taken his own life.
Russia in 2021 was rocked by two separate tragic killing sprees - at a school in the city of Kazan and at a university in Perm - that spurred MPs to tighten laws regulating access to guns.
