People in various places around the world said on social media that they were disconnected on WhatsApp, which is a unit of Facebook.

In Hong Kong, many WhatsApp users complained that they could not send messages to others on Friday afternoon as the instant messenger service was down.

“Our service is experiencing a problem right now. We are working on it and hope to restore the functionality shortly. Sorry for the inconvenience,” WhatsApp said in a notice on its platform.

People began using other social media platforms such as Facebook, Twitter and WeChat to get more information about the incident.

Twitter users were using the hastag #WhatsAppDown to communicate during the period the messenger system was not working.

WhatsApp’s services were resumed at around 5pm.