Apple's App Store and iTunes Store are both experiencing outages at the current time, according to Apple's System Status page.
The outage started this afternoon, and affected users may see slow App Store performance or may be unable to use the App Store at all. There are numerous reports on social media from users who are seeing App Store issues.
It is not clear what caused the outage nor how long it will last, but we'll update this article when the issue is resolved.
Update: This issue has been fixed and the App Store and iTunes Store are once again up and running.