Multiple users said that heading to home page of Facebook showed only a "service unavailable" message.
The outage comes at a particularly sensitive time for the company.
In addition, Facebook is still on the defensive after a blockbuster report in The New York Times detailed how the company reacted to increased scrutiny and security breaches from Russian accounts ahead of the 2016 USA presidential election.
Oil falling deeper into 'bear territory' amid waning demand, analysts say
Prices were lifted by a report of an unexpected decline in U.S. commercial crude inventories and record Indian crude imports. Record crude imports by India of nearly 5 million barrels per day (bpd) also supported prices, traders said.
Tweeted banter included jokes about people actually getting work done, meeting one another in real life, or flocking to Twitter while not being able to get to Facebook.
Facebook users around the world experienced trouble with the site. "We're working to resolve the issue as soon as possible", a Facebook spokesperson tells Mashable in a statement.
Problems appear to have started just before 1pm after a brief outage early this morning.
FACEBOOK and Instagram have been hit by a service outage as some users around the world report being unable to access the social networks.