Sen. Tom Coburn (R-Okla.) said Wednesday that a government whistleblower has revealed that Immigration and Customs Enforcement officials are using prosecutorial discretion to end deportation proceedings against some of the tens of thousands of illegal immigrant children flooding across the border.

Coburn said he spoke to an ICE agent whistleblower, who provided ten documented examples in which ICE terminated requirements for immigrant children to appear before a deportation hearing.

U.S. Immigration and Customs Enforcement Principal Deputy Assistant Secretary Thomas Winkowski said Wednesday that he wasn’t aware that ICE officials to terminating deportation proceedings for some child immigrants. (AP Photo/Susan Walsh)

“The reason for these terminations… is listed as ‘prosecutorial discretion,’ ” Coburn said. Coburn said the documents he reviewed were marked “PD” to indicate a termination of deportation proceedings.

Coburn revealed this during today’s Senate hearing on the border crisis, and asked Deputy Assistant Secretary for ICE Thomas Winkowski what authority ICE has to waive the deportation process. He also asked how many times this has been used, and what happens to children who benefit from this process.

But Winkowski said he wasn’t aware of any use of prosecutorial discretion.

“I’m not familiar with this particular case,” he said. “I don’t know all the details of why the NTA [notice to appear] was declined to be filed. I’ll be more than happy to look into it.”

The phrase “prosecutorial discretion” has irked Republicans in the past, and on the same issue of immigration. In 2012, the Obama administration said it would use its prosecutorial discretion to defer deportation action against younger illegal immigrants who were brought to the United States as children, in most cases.

Republicans have since blasted that decision as one that is attracting even more illegal immigrants across the border.