A data breach at the US retailer, Target, will affect up to 70 million people, 30 million more than what the company first estimated in mid-December.
In addition to the credit and debit card data stolen from Target, thieves also took customer names, mailing addresses, phone numbers or email addresses, Target said in a statement released Friday.
Target found the additional affected customers and the additional information that was taken in its ongoing forensic investigation, the company said.
Target will attempt to contact those people affected by the breach in cases where it has a customer's email address, the company said. Target will not ask customers for any personal information in those emails.
Target announced in mid-December that thieves had taken credit and debit card information between Nov. 27 and Dec. 15.
"I know that it is frustrating for our guests to learn that this information was taken and we are truly sorry they are having to endure this," Gregg Steinhafel, Target's chairman, president and CEO, said in a statement. "I also want our guests to know that understanding and sharing the facts related to this incident is important to me and the entire Target team."
Target has pledged to pay for the costs of any fraudulent charges related to the breach. The company is also offering one year of free credit monitoring and identity theft protection to customers who shopped at the company's US stores.
More information about the breach is available at Target's website.
Grant Gross covers technology and telecom policy in the U.S. government for The IDG News Service. Follow Grant on Twitter at GrantGross. Grant's email address is email@example.com.