A handful of agency employees who gave their login details to Snowden were identified, questioned and removed from their assignments, said a source close to several U.S. government investigations into the damage caused by the leaks. 

Snowden may have persuaded between 20 and 25 fellow workers at the NSA regional operations center in Hawaii to give him their logins and passwords by telling them they were needed for him to do his job as a computer systems administrator, a second source said.

  The revelation is the latest to indicate that inadequate security measures at the NSA played a significant role in the worst breach of classified data in the super-secret eavesdropping agency's 61-year history.