AT&T Inc. says there appears to have been an "organized attempt" to break into mobile customers' online accounts, but no accounts were breached.
The Dallas company says hackers used automated programs to try to link mobile numbers and account log-in credentials, which they then hoped to use to access customer accounts on AT&T's website.
AT&T says it is investigating the source or intent of the attempt to gather information.
The company says the attacks affected less than 1 percent of its total mobile subscribers. It says it is advising the account holders involved "out of an abundance of caution."