By YOUKYUNG LEE
AP Technology Writer
SEOUL, South Korea (AP) -- Facebook suffered a widespread outage lasting an hour on Tuesday affecting users worldwide.
The glitch reported in Asia, the United States, Australia and the U.K. affected access from PCs and Facebook's mobile app. The social media giant's Instagram service was also inaccessible.
On its website for developers, Facebook said the "major outage" lasted one hour. It said its engineers had identified the cause but did not elaborate.
Facebook has about 1.35 billion active users and Instagram has some 300 million.
News of the Facebook outage set rival social network Twitter alight, propelling the hashtag "facebookdown" to top trend on the site. It comes ahead of Facebook reporting its quarterly earnings on Wednesday.
As access to Facebook returned, some users in Asia reported that the site was loading slowly or not offering full functionality.
The temporary loss of service may be Facebook's biggest outage since Sept. 24, 2010 when it was down for about 2.5 hours.