Education authorities in southwestern Poland are looking into allegations that a primary school teacher taped small children's mouths shut to silence them.

A suspicious mother secretly recorded the teacher's classes. In the voice recordings published by TVN24, a woman is heard threatening that she will again put adhesive tape over a child's mouth. "But it hurt," a small child is heard pleading.

The woman's voice also says "I will take your tapes off during breakfast," as children's voices can be heard in the background.

The director of the village school in Szczodre, Agnieszka Cichorek, says she was not aware of the teacher's behavior, and the teacher has since been fired.

Janina Jakubowska, a spokeswoman for the education authorities, said Tuesday that regional school inspectors are gathering facts in the case.