Facebook and Instagram appear to have crashed in an outage that's affecting users across the globe.

Neither of the social networks are working - causing users everywhere to take to rivals Twitter to vent their frustrations.

It's not yet clear what has caused the outage - but website downdetector.com shows the places in the world affected by the problems.

Areas showing problems with Facebook

There's a big red blob over the UK which indicates users across the country are unable to access the sites.

Problems are also showing up on both the east and west coast of the United States; Buenes Aires, Rio de Janeiro and areas of Peru in South America; across big cities in eastern and western Europe; Singapore and the Phillipines.

We will update this story as more information becomes available.