Rep. Darrell Issa (R-CA) said on a conference call Wednesday evening that he will try to get a White House official who may have had knowledge of the botched Fast and Furious gunrunning operation to testify before the House Oversight and Government Reform Committee.

But Issa, who chairs the committee, was not optimistic about the effort. “Try? Yes,” he said, asked whether he would try to get the official into his committee room. But Issa noted that there has been “political interference at the highest level” throughout the Oversight committee’s Fast and Furious investigation.

The White House official in question is National Security Director for North America Kevin O’Reilly. During a Tuesday Oversight hearing on Fast and Furious, former ATF Special Agent Bill Newell, who was instrumental in implementing the operation, said that he had spoken with O’Reilly about Fast and Furious as early as September 2010. Whether O’Reilly was made aware that the ATF had let guns cross the border into Mexico as part of the investigation was not clear.

Newell’s admission is the first indication that White House officials were aware of the Fast and Furious program while it was ongoing. The email was leaked to the Oversight Committee by a whistleblower, Issa said; it was not released willingly by the White House.

CBS News reported on the details of the message on Wednesday:

Congressional investigators obtained an email from Newell to O’Reilly in September of last year in which Newell began with the words: “you didn’t get this from me.”

“What does that mean,” one member of Congress asked Newell, ” ‘you didn’t get this from me?’ ”

“Obviously he was a friend of mine,” Newell replied, “and I shouldn’t have been sending that to him.”

Newell told Congress that O’Reilly had asked him for information.

“Why do you think he asked for that information,” Congressman Darrell Issa (R-CA) asked Newell.

“He was asking about the impact of Project Gunrunner to brief people in preparation for a trip to Mexico… what we were doing to combat firearms trafficking and other issues.”