House Oversight and Government Reform Chairman Darrell Issa visits Meet the Press to update David Gregory on the latest developments in his panel's investigation into the Benghazi attacks.

A top GOP critic pushed back Sunday on charges that Republican efforts to investigate last year's Benghazi attack are designed to inflict political damage on former Secretary of State Hillary Clinton.

"Hillary Clinton's not a target," said House Oversight and Government Reform Committee Chairman Darrell Issa on NBC's Meet the Press. "President Obama is not a target."

Issa, who heads a panel probing the assault on the diplomatic outpost that killed four Americans, including Ambassador Chris Stevens, said he will seek depositions from Benghazi review board heads Ambassador Thomas Pickering and retired Adm. Mike Mullen, the former chairman of the Joint Chiefs of Staff.

The interagency process of modifying talking points in the wake of the attack scrubbed the fact that the incident was "a terrorist attack from the get-go," Issa said Sunday.

"The American people were effectively lied to for a period of about a month," he charged. "That's important to get right."

Ambassador Thomas Pickering responds to Congressman Darrell Issa's claim that the diplomat should testify on the Benghazi incident.

Issa's committee held a high-profile hearing last week on the Benghazi attack. The California Republican claimed Sunday that Pickering - the man who led an independent review of the attacks on behalf of the State Department - refused to testify at that hearing.

Pickering flatly denied that he was unwilling to appear.

"I said the day before the hearings I was willing to appear, to come from the very hearings [Issa] excluded me from," Pickering told NBC's David Gregory. "We were told the majority said I was not welcome at that hearing; I could come at some other time."

Issa said he was unaware of Pickering's late notice, which the ambassador said he communicated through the White House, but added that a private deposition - which he intends to formally request Monday from the ambassador - is the more appropriate way to begin the inquiry.

"The fact is we don't want to have some sort of a stage show," Issa said.

Issa spokesman Frederick Hill said in a statement that Oversight committee Republicans never received a request for Pickering to testify.

"We challenge him to name the White House official who he was in contact with and the White House official whom he falsely says relayed his interest in testifying to Chairman Issa," Hill said.

Republicans have been dogged in their questioning of the administration's response to the attack, with leaked documents revealing last week that officials at the State Department suggested edits to talking points that erased references to terrorist groups.

While Hillary Clinton has stated publicly that she was not involved in that editing process, criticism of the former State Department chief and much-discussed possible presidential candidate has been a strong subtext of the Benghazi debate.

Sen. Dianne Feinstein discusses remarks on the House probe into the Benghazi attacks and details amendments made in markup to the Senate immigration overhaul.

Senate Intelligence Committee chair Dianne Feinstein, a Democrat, said on Meet the Press that Issa's panel has deliberately put Clinton's ambitions in its crosshairs.

"My concern is when Hillary Clinton's name is mentioned 32 times in a hearing, then the point of the hearing is to discredit the Secretary of State, who has very high popularity and may well be a candidate for president," Feinstein said.

Likely 2016 Republican candidate Sen. Rand Paul excoriated Clinton in a speech Friday in key campaign state Iowa, saying her role in the Benghazi episode "should preclude her from holding higher office."

"I think that's nonsense," Feinstein said of Paul's claim. "And I think the American people will think that's nonsense."

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