AT&T on Monday acknowledged an organized attempt to hack information on fewer than 1% of its 100 million wireless customers, but it said no accounts were breached.

A spokesman said the hackers appear to have used auto-script technology to find whether AT&T telephone numbers were linked to online AT&T accounts. He didn't elaborate, but said an investigation is continuing.

The spokesman said fewer than 1% of AT&T's 100.7 million wireless subscribers were contacted by hackers through email -- a number that could mean about 1 million customers were affected.

"Our investigation is ongoing to determine the source or intent of the attempt to gather this information," AT&T spokesman Mark Siegel said in an email.

He said the AT&T account holders were advised of the attempt "out of an abundance of caution."

Matt Hamblen covers mobile and wireless, smartphones and other handhelds, and wireless networking for Computerworld. Follow Matt on Twitter at @matthamblen or subscribe to Matt's RSS feed. His e-mail address is mhamblen@computerworld.com.