WASHINGTON (TIP): The State Department acknowledged on Thursday it could not find any record of part or all of 15 emails from Hillary Clinton dating from her time as secretary of state, copies of which have been given to US lawmakers.

A stash of thousands of emails has been turned over to a congressional panel investigating the 2012 attack on a US mission in Libya by longtime Clinton confidante and friend Sidney Blumenthal.

But in comparing the Blumenthal cache with some 30,000 emails Clinton has given to the State Department, officials admitted there were “a limited number of instances, 15, in which we could not locate all or part of the content of a document from his production within the tens of thousands of emails she gave us.”

“The substance of those 15 emails is not relevant to the 2012 attacks in Benghazi,” the State Department official stressed, asking not to be named.

The email correspondence has triggered a political row after Clinton — now bidding to be elected America’s first woman president in 2016 elections — revealed she had used a private server and email address during her time as secretary of state from 2009 to early 2013.

A first slew of 296 emails relating to Libya and the 2012 attack on the US mission in Benghazi in which four Americans were killed was made public in May after a judge ordered that they be released.

The next batch from some 55,000 pages of correspondence is due to be released by the State Department on June 30.