Hillary Clinton email controversy continues with new batch found

U.S. President Barack Obama'sadministration has discovered a chain of emails that Hillary Rodham Clinton failed to turn over when she provided what she said was the full record of work-related correspondence as U.S. secretary of state, officials said Friday.

This adds to the growing list of questions related to the Democratic presidential front-runner's unusual usage of a private email account and server while in government.

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The messages were exchanged with David Petraeus, a retired U.S. army general, when he headed the military's U.S. Central Command, which was responsible for running the wars in Iraq and Afghanistan.

They began before Clinton entered office and continued into her first days at the U.S. State Department. They largely pertained to personnel matters and don't appear to deal with highly classified material, officials said, but their existence challenges Clinton's claim that she has handed over the entirety of her work emails from the account.