An armed man opened fire in a kindergarten on Tuesday in Russia's central Ulyanovsk region, leaving at least four people dead, local authorities said. 

"Two children and a teacher were killed, a junior teacher was injured - she is receiving medical treatment," the region's governor Alexey Russkhikh said on Telegram.

The shooting took place in the "Ryabinka" kindergarten near the town of Veshkaima, he said. 

Russian rights ombudsman Tatyana Moskalkova identified the shooter as local resident Akhtyamov Ruslan, born in 1996, and described him as "mentally ill".  

She said on Telegram he used a double-barrel Izh-26 shotgun that was registered under a different person's name and committed suicide by "shooting himself in the face". 

Moskalkova said the two murdered children were born in 2016 and 2017. 

The owner of the gun was later found dead, according to deputy governor Alexander Korobko. 

Local rights ombudsman Sergei Lulkov said the shooter had "no links" to the murdered teacher and children, the Interfax news agency reported. 

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 lawmakers to tighten laws regulating access to guns.