Facebook and Instagram have suffered a global outage.
Thousands of users have reported being unable to access the social media sites across Europe including the UK, the United States, South America and the Far East.
Website Downdetector, which tracks technology failures online, indicated tens of thousands of problems were reported on both sites between 3pm and 6pm GMT on Wednesday (early Thursday AEDT).
Almost 90 per cent of problems on Facebook in the UK were reported as total blackouts or users being unable to log in, while on Instagram the core issue was with its news feed.
Facebook, which also owns Instagram, wrote on its developer site: "We are currently experiencing an increased level of API errors. We are investigating the cause and we'll post updates when we have more information."
Many users used other social media outlets to vent their frustration, with the hashtag FacebookDown trending on Twitter.
