Facebook and Instagram have been hit by a service outage as some users around the world report being unable to access the social networks.
Users of both platforms have reported being unable to open pages or sections on the apps, with Facebook's developer website confirming the company is currently looking into the issue.
"We are currently experiencing issues that may cause some API requests to take longer or fail unexpectedly," a message on the Facebook for developers page confirmed.
"We are investigating the issue and working on a resolution."
Facebook has more than 2.2 billion users worldwide, while Instagram - which is owned by Facebook - has more than one billion active users.
According to website status monitoring service Down Detector, the problems at both sites began just before 1pm on Tuesday in the UK, but problems have also been reported across Europe, on the east coast of the United States and in Asia.
Neither Facebook or Instagram has commented on the cause of the issue.