Facebook has admitted hiring workers to listen in to private conversations on its Messenger service - but only in America.
The company's suspended a controversial programme that saw hundreds of contractors transcribing the recordings.
Contractors, speaking to Bloomberg on condition of anonymity, the contractors said they were told to transcribe conversations but not why the social media giant wants it done.
They said the company did not tell them where the audio came from - but confirmed that the conversations sometimes include vulgar content.
Ireland's Data Protection Commission (DPC) has said it is looking at the practice to see if it breached European privacy rules.
In a statement however, Facebook said the test wasn't subject to GDPR - because it was only ever carried out in the US.
It said no EU users were affected by or included in the test which was aimed at helping people to understand the content of voice clips.
In a statement earlier, the DPC said it was seeking "detailed information" from Facebook on the practice.
The commission said: "Further to our ongoing engagement with Google, Apple and Microsoft in relation to the processing of personal data in the context of the manual transcription of audio recordings, we are now seeking detailed information from Facebook on the processing in question and how Facebook believes that such processing of data is compliant with their GDPR obligations.”
The Irish authority has responsibility over Facebook in Europe as the social media giant's EU headquarters are in Dublin.
Facebook said it has now suspended the practice.
“Much like Apple and Google, we paused human review of audio more than a week ago,” it said.
It said contractors were hired to check that the app's artificial intelligence technology was correctly transcribing the messages.