We are having network problems with some of the servers in USA and EU locations. We are working with our upstream providers to isolate and resolve the issue as soon as possible. When we know more about the problem we will post an update here.
Update: The latency appears to be over. We were unable to locate the root of the problem. The servers involved were online but unreachable from some locations. If you are still experiencing issues please submit a support ticket with the output from mtr if you are using Linux/OS X or pathping if you are using Windows.
Update: It seems that this was due to a bug in the software of one of the intermediate routers. Our upstream provider is working with the router vendor for possible fixes.