Facebook and Instagram users have been unable to access services for the second time in a week.
The social media giants apologised to users who are unable to refresh their home pages, though the outage appears to be less widespread than on Monday.
Around 2,000 people reported being unable to access Facebook at around 8pm on Friday, according to the outage tracking website Downdetector.
Two hours later, both Instagram and Facebook reported the problems on the platforms had been fixed.
Facebook said on Twitter: "We're aware that some people are having trouble accessing our apps and products.
"We're working to get things back to normal as quickly as possible and we apologise for any inconvenience."
Instagram added: "We know some of you may be having some issues using Instagram right now.
"We're so sorry and are working as quickly as possible to fix."
A couple of hours later, it issued an update saying: "Things have been fixed, and everything should be back to normal now.
"Thank you for bearing with us (and for all the memes this week)."
The Facebook post said: "We're so sorry if you weren't able to access our products during the last couple of hours.
"We know how much you depend on us to communicate with one another.
"We fixed the issue - thanks again for your patience this week."
No explanation was given for the disruption.
Monday's outage, which affected Facebook, Instagram and WhatsApp, left billions of the platforms' users unable to get online for almost six hours.
Facebook, which owns all three services, said the glitch was caused by an error during a routine maintenance job and "not by malicious activity".