Users around the world are experiencing difficulty accessing social media sites Instagram and Facebook as well as encrypted messenger WhatsApp.
Those in the UK, US and Europe appear to be hardest hit in the latest in a string of outages.
Reports have come in from further afield, including Australia, Brazil, Colombia, Japan, Mexico, The Philippines, Russia, Singapore, South Africa and Uruguay.
‘We’re aware that some people and businesses are currently having trouble uploading or sending images, videos and other files on our apps,’ a Facebook spokesman said.
‘We’re working to get things back to normal as quickly as possible.’
Users began to report the issues in their hundreds to outage tracker Down Detector shortly before 2pm BST (9am ET / 6am PT).
They have continued to grow ever since, as more and more users across the US attempt to log on for the first time today.
Reports for Instagram alone via the site had reached 4,300 at the time of writing.
Instagram issues centre around posting to the news feed, seeing stories and loading content.
Facebook users say they are having trouble logging in and accessing their feeds, as well as viewing or posting pictures.
WhatsApp is failing to send or receive messages, as well as offering a poor connection and a small number of users are unable to log-in.
Bemused and confused users took to social media to bemoan the outage and ask if others were experiencing any difficulty getting online.
Briana said: ‘Dear Instagram PLEASE FIX YOUR APP. Your news feed is almost always down.
‘Please do some major maintenance and fix all your problems!!! UPGRADE YOUR SERVERS TOO!!! – Yours truly one pissed off Instagrammer.’
Eric Norton, from Daytona Beach, Florida, said: ‘It’s going to be one of those days again. #FacebookDown #InstagramDown Guess it’s back to living real life instead…’
Facebook has experienced a number of outages affecting one or more of its apps – Instagram, Facebook and WhatsApp.
As the servers dealing with all three share information, it is increasingly likely that an issue affecting one Facebook service will also hit others.
In the early weeks of June, Instagram was hit with an outage that affected users around the world and lasted for several hours.