Some network operators are using the little snippets of text that run along the top of smartphone displays, where connection signals are usually found, to advise people to stay indoors.
Carriers like Vodafone and Orange are using it to promote coronavirus-related public health advice.
The messages have been popping up on phones in the US and in parts of Europe, but not the UK as yet, though the country's network operators did send out a 'stay home' text message on behalf of the UK government on Tuesday.
Social media consultant Matt Navarra spotted the new messages on his phone and began tweeting images of it on Tuesday afternoon. German Vodafone customers are also reporting seeing the messages.
Navarra's initial tweet attracted a flood of replies showing the same message in different languages around the world. This included "Stamacasa" in Romania, "YoMeQuedoEnCasa" in Peru, and "DiRumahAja" in Indonesia.
Strangely, users in Belgium, France, India and Nigeria reported seeing messages in either English or in another native language, depending on the carrier. In some areas, the messages only appear to show up when Wi-Fi is switched off, according to Nevarra. At the moment, UK Vodafone customers are unable to see the messages regardless of whether they have Wi-Fi switched on or off.
On Tuesday, the UK government asked the country's network operators to send 'stay at home' messages to mobile phones in a bid to stop mass gatherings and contain the spread of COVID-19.
