Elon Musk slammed WhatsApp on Twitter today amid reports the Mark Zuckerberg-owned app is listening to users.

Musk said the messaging app 'cannot be trusted' in response to a tweet thread from one user who said WhatsApp accessed their phone's mics while they slept.

It is the second time in just a few weeks that the Twitter and Tesla billionaire has jabbed at his tech rival Zuckerberg, accusing him of 'bias' for supporting Democrats through his campaign donations.

Musk's latest barb came in response to a screenshot shared by Foad Dabiri, who showed how his WhatsApp mic was switched on nine times between 4:20 am to 6:53 am while he was asleep.

WhatsApp responded to the issue on its Twitter account, noting that Dabiri's incident 'is a bug on Android.' But the issue has persisted for months.

The incident is not limited to Dabiri, as many WhatsApp users have reported seeing the microphone activated on the background over the past month or more.

Some users have suggested restarting the device will fix the issue or 'tap the mic access notification shortcut to toggle it off and then turn it back on,' a Redditor shared.

When DailyMail.com asked Meta for more details, a spokesperson referred to the Twitter post.