Dec 14 (Reuters) - Yahoo Inc
* has identified data security issues concerning certain yahoo user accounts
* Believes this incident is likely distinct from incident company disclosed on september 22, 2016
* Yahoo believes an unauthorized third party, in august 2013, stole data associated with more than one billion user accounts
* stolen user account information may have included names, email addresses, telephone numbers, dates of birth, hashed passwords
* Says payment card data and bank account information are not stored in system company believes was affected
* says co has connected some of this activity to same state-sponsored actor believed to be responsible for data theft co disclosed on september 22, 2016
* "Yahoo is notifying affected account holders, and has invalidated forged cookies"
* Important security information for Yahoo users
* Yahoo has taken steps to secure user accounts and is working closely with law enforcement.
* company has not been able to identify intrusion associated with this theft
* stolen user account information may also include in some cases, encrypted or unencrypted security questions and answers
* based on ongoing investigation, company believes an unauthorized third party accessed company's proprietary code to learn how to forge cookies Source text for Eikon: Further company coverage: