This was announced by local police's press service, Censor.NET reports.
"According to preliminary information, the kids aged seven to 10 were playing in the yard. Witnesses say an explosion occurred inflicting shrapnel wounds to all four of the children," police said.
Two children were brought to a hospital in grave condition. One of them has shrapnel wounds to abdomen, another had a limb amputated.
"The other two are taken care of as well. Police is looking into the circumstances of the explosion and the origin of the ammunition," the report reads.