Updated 10.40am
WhatsApp was down in several countries including Malta this morning, with several users reporting problems in sending and receiving messages.
As of 10am, many users' messages are not being delivered and the service's web service, which allows users to sync the app with their computer, is also not working.
"Our service is experiencing a problem right now. We are working on it and hope to restore the functionality shortly," the Facebook-owned messaging service wrote in its 'help' section.
The outage did not appear to be a complete one, with some users telling Times of Malta they were still able to send and receive messages during the down period.
By 10.30am, service appeared to have resumed.
According to website server checker Down Detector, most problems were reported in Europe and parts of Asia. It is not yet clear whether server problems also affected users in America and Latin America, where it is currently nighttime.