Lowell McAdam, the Verizon Wireless chief executive officer, told employees in an e-mail Wednesday that the telephone involved had not been active for several months, CNN reported Thursday. He said anyone looking at the records would get phone numbers of calls to or from the phone but no information on Obama's e-mail or voice mail.

Robert Gibbs, a spokesman for the transition team, said the Secret Service had been alerted. But he said he knew of no criminal investigation.

Employees who accessed the records for "anything other than legitimate business purposes will face disciplinary action, up to and including termination," McAdam said in his e-mail.

During the 2008 presidential campaign, the State Department discovered that some contractors had been looking at passport files of presidential candidates and celebrities.