The Federal Bureau of Investigation will inverstigate the security breach of Apple's iPad that exposed personal information of AT&T Inc customers. On Wednesday, Gawker was informed of the flaw and given a list of the email addresses by a group of hackers. The information exposed in the breach included subscribers' email addresses, coupled with an associated ID used to authenticate the subscriber on AT&T's network, known as the ICC-ID, Gawker said. ICC-ID stands for integrated circuit card identifier and is used to identify the SIM cards that associate a mobile device with a particular subscriber.

The issue was corrected by Tuesday and AT&T has turned off the feature that provided the email addresses, the company said.

"The FBI is aware of these possible computer intrusions and has opened an investigation to address the potential cyber threat," FBI spokesman Jason Pack said on Thursday, Reuters reports.

The quick FBI probe into the security flaw came amid reports of several high-ranking government officials on the list of iPad owners with compromised personal information.

The iPad, launched in April, has already sold more than 2 million units worldwide.

Dell and Hewlett-Packard Co are also trying to offer competitive devices onto the market, and the security breach could pose a potential embarrassment for Apple's 2-month-old device.