White House: Obama stands by 'not spying on Americans' comment

He also said the president was "not opposed to additional measures that members of Congress think would be helpful in inspiring greater public confidence in these programs."

The Post's story revealed that, on thousands of occasions since Congress granted the NSA broad new surveillance powers, employees at the agency violated federal statute and executive orders to conduct unauthorized surveillance of Americans or foreign intelligence targets who had traveled to the United States. 

Violations included everything from typographical errors to failure to follow standard operating procedures.

Lawmakers from both sides of the aisle, including top Democrats like Sen. Patrick Leahy (D-Vt.) and House Minority Leader Nancy Pelosi (D-Calif.), expressed outrage last week at the revelations. 

Leahy said in a statement he would "continue to demand honest and forthright answers from the intelligence community."

“I remain concerned that we are still not getting straightforward answers from the NSA," Leahy continued.

But John DeLong, the NSA's director of compliance, defended the agency in a call with reporters on Friday, saying that the number of willful violations was "tiny."

“No one at NSA thinks a mistake is okay,” he said.

On Monday, Earnest highlighted the fact that of the 2,776 incidents reported in the audit, 1,904 of them were instances where foreigners who traveled into the United States continued to have their cellphones wiretapped without obtaining an individual warrant.

"Understanding the facts of this complicated policy is important," Earnest said.