Confirming media reports that agency workers used surveillance technology in their private life -- a practice jokingly known as "loveint" -- the NSA's inspector general, General George Ellard, released a letter to a US senator disclosing details of the romantic snooping.
The admission represented yet another setback for the agency as it struggles to defend its surveillance activities in the wake of revelations from intelligence leaker Edward Snowden, who lifted the lid on the NSA's vast digital dragnet.
These are procedures that allow the agency to search telephone records and tap communications of suspects abroad.
The NSA's inspector general office had two open investigations into the misue of these powers and is reviewing an allegation for another possible probe, Ellard wrote in the letter dated September 11.
In many of the cases described in the letter, the NSA employee who had acted improperly resigned before any disciplinary action was taken and government authorities did not prosecute them.
She quit the agency before "proposed discipline was administered," it said.
And in 2011, another employee tried to search for call records on his home telephone number as well as the number of his girlfriend, who was a foreign national.
His request on his own number was rejected as the agency bars spying on Americans communications without a court order, but he succeeded in collecting data on his girlfriend's phone number.
He told investigators he performed the query "out of curiosity" and he retired in 2012 before any disciplinary action had been taken.
Her co-worker alerted the inspector general's office and an investigation found the boyfriend had searched nine telephone numbers of foreign women and listened to collected phone conversations while he was abroad, all "without a valid foreign intelligence purpose," the agency said.
