House Republicans pushed ahead Monday with their investigation of the deadly assault on the U.S. diplomatic mission in Benghazi, Libya, last year as President Barack Obama asserted that GOP charges of a cover-up are baseless.

The latest Republican focus is the independent review that slammed the State Department for inadequate security at the installation before the twin nighttime attacks that killed Ambassador Chris Stevens and three other Americans on Sept. 11, 2012.

Rep. Darrell Issa, R-Calif., chairman of the House Oversight and Government Reform Committee, asked the two authors of the investigation — veteran diplomat Thomas Pickering and retired Adm. Mike Mullen, the former chairman of the Joint Chiefs of Staff — to meet privately with committee staff to answer questions about their review. Democrats countered that if Congress wants to talk to them, Issa should hold a full open hearing.

Republicans insist that the Obama administration misled Congress and the American people in the immediate aftermath of the attack, trying to play down an act of terrorism that would reflect poorly on Obama weeks before the 2012 presidential campaign.

Emails disclosed Friday showed that State Department and other senior administration officials pushed for references to prior warnings and al-Qaida to be deleted from the talking points used by U.N. Ambassador Susan Rice five days after the attack. One email suggested that Congress could use those issues as ammunition against the State Department.

At a White House news conference, Obama dismissed the GOP focus on the talking points as a politically driven “sideshow,” pointing out that he said “act of terror” on Sept. 12 and the talking points assessment was similar to the daily presidential briefing he had received.

He also noted that Matt Olsen, director of the National Counterterrorism Center, told Congress that Benghazi was a terrorist attack with potential links to al-Qaida three days after Rice’s appearance on five Sunday talk shows.

“So if this was some effort on our part to try to downplay what had happened or tamp it down, that would be a pretty odd thing that three days later we end up putting out all the information that in fact has now served as the basis for everybody recognizing that this was a terrorist attack and that it may have included elements that were planned by extremists inside of Libya,” the president said. “Who executes some sort of cover-up or effort to tamp things down for three days?”

While Obama did refer to Benghazi as an act of terror, the president also cited protests over an anti-Islamic video in several interviews days after the attack, as did Rice on several Sunday news shows. He said Monday that “nobody understood exactly what was taking place during the course of those first few days.”

The emails comprising the inter-agency discussion on how to best describe the events in Benghazi were shared with Congress as a condition for allowing the nomination of John Brennan for CIA director to move forward.

The general counsel for the office of the Director of National Intelligence briefed members and staff from the Senate Intelligence panel and leadership on the emails on Feb. 15 at a session in which staff could take notes. A similar briefing took place on March 19 for the House Intelligence panel and leadership staff, according to a senior administration official.

The official spoke on condition of anonymity because the individual was not allow to publicly discuss the process.

New details on the emails emerged last week. Obama argued that lawmakers had reviewed them several months ago but suddenly they were treated as fresh revelations.

“There’s no ‘there’ there,” the president said.

Issa has argued that there is and Congress needs to get to the bottom of it. He wants to hear from Pickering and Mullen about their investigation and he asked that they turn documents, communications, lists of witnesses, notes and other material by Friday.

He pointed to the testimony of three State Department witnesses last week who criticized the Accountability Review Board’s work as incomplete and flawed.

“The White House and the State Department have touted the ARB’s report as the definitive account of how and why the Benghazi attacks occurred,” Issa said in separate letters to Pickering and Mullen. “It is necessary for the committee to understand whether the criticisms of the ARB’s work that we heard from witnesses on May 8, 2013 are valid.”

But the top Democrat on the committee, Rep. Elijah Cummings of Maryland, told Issa that he should bypass private depositions from the two men and go directly to an open hearing on May 22. Issa said to Pickering and Mullen that they would work out a hearing for their public testimony at a later date.

Their blistering report found that “systematic failures and leadership and management deficiencies at senior levels” of the State Department meant that security was “inadequate for Benghazi and grossly inadequate to deal with the attack that took place.” They absolved former Secretary of State Hillary Rodham Clinton, faulting lower level State Department officials.

Four State Department officials were reassigned or resigned in the wake of the Pickering-Mullen report.

“We knew where the responsibility rested,” Pickering, a career Foreign Service officer who has worked for Republican and Democratic administrations, said Sunday.

(AP)