GENEVA (AP) Switzerland's leading telecommunications company says four internal data files that included employee emails were leaked to a top newspaper.

Swisscom says the Neue Zuercher Zeitung was given backup files from 2008 to 2010 that contained internal data. It says the newspaper has returned three of the files.

The newspaper says it received the leaked files somewhat mysteriously a few months ago and used them for a story Wednesday in which it said they include company and customer information including 600,000 phone numbers.

The company says it is pressing criminal charges "against persons unknown," since the breach appears to be "motivated by criminal intent." Swiss prosecutors were not immediately available for comment.