There were widespread reports that the Etisalat mobile phone network crashed in Abu Dhabi and Dubai on Thursday evening, with the impact still being felt on Friday.
Etisalat users are still experiencing mobile and internet network crashes in Abu Dhabi, Dubai and Ajman according to downdetector.com, which shows that the problem seems to have downgraded overnight, but persists.
Callers were unable to make or receive calls from mobile phones or from landlines to mobile numbers.
The website downdetector.ae showed outage reports in both major cities, with a huge spike just after 5pm on Thursday.
In Ajman, some users said that the problem started on Wednesday morning. "We didn't expect it to be a crash, we thought it's something minor and will pass quickly," said Ahmad Mahmoud, 45, a dentist from Ajman.
"But it's still down. One out of every five calls works out, and the internet is practically as good as dead."
There was no initial explanation on the phone company's own site, and Etisalat have not yet commented on the outage since being contacted by The National.
On Thursday customers used Twitter in an attempt to discover what was going on.
Services from landline to landline appear to be working normally.
The UAE has two mobile phone networks, Etisalat and Du.