The German telecoms regulator has banned the sale of children's smartwatches that allow users to secretly listen in on nearby conversations.
The move is the latest in a string of actions taken by the Federal Network Agency, or Bundesnetzagentur, against devices that allow people to snoop on each other.
The agency said the smartwatches, aimed at 5 to 12-year-olds, come with a SIM card and limited telephony functions – allowing nearby chatter to be monitored from afar, which goes against Germany's strict anti-surveillance laws.
"The watches are regarded as unauthorised transmitting equipment," said Bundesnetzagentur president Jochen Homann.
He added that investigations had found "that parents were using them to eavesdrop on teachers in lessons".
The agency said it had already taken action against "several offers on the internet" and indicated that owners weren't off the hook yet.
"If the Federal Network Agency has knowledge of the buyers of such devices, it will give the evidence and the evidence of this to the authority," the agency said.
"It is recommended for parents to take responsibility for destroying the devices themselves and to keep proof of this."
For instance, they could send the device to a waste management station for destruction and then get a letter of proof, or take photos that "clearly show the destruction of the spyware in question" to show that the device is inoperative.
In February this year, the agency banned Genesis Toys' Cayla doll as an illegal surveillance device as it came with a microphone and captures children's speech.