A frustrated President Obama said Monday that the Republican focus on the administration’s response to last year’s fatal attacks in Benghazi, Libya, is a “sideshow” with obvious partisan motives.

“There’s no ‘there’ there,” Obama said in response to the ongoing criticism of the administration’s initial public response to the assault.

Last week, edited versions surfaced of the administration’s talking points for congressional leaders and other officials shortly after the attacks, which killed four Americans. The versions showed the State Department and CIA battling over who would explain the events to the public. Republicans assert that the differing versions constituted a coverup.

Obama scoffed at the idea the administration was hiding anything and said continuing to politicize Benghazi is disrespectful to the Americans who died there. “We dishonor them when we turn things like this into a political circus,” Obama said during a morning White House news conference with British Prime Minister David Cameron.

“The whole issue of talking points, throughout this process, frankly, has been a sideshow” that distracts from an examination of the serious shortcomings in diplomatic security revealed by the assault and by harsh assessments based on an investigation afterward, Obama said.

Ambassador J. Christopher Stevens, communications officer Sean Smith and CIA contractors Tyrone Woods and Glen Doherty died when militants overran two U.S. compounds in the restive Libyan city on Sept. 11.

Obama’s public frustration over an issue that has unified congressional Republicans and animates their conservative political base came as one of the Republicans leading the charge asked leaders of a State Department investigation in Benghazi to answer more questions from lawmakers.

Rep. Darrell Issa (R-Calif.), chairman of the House Oversight and Government Reform Committee, asked former diplomat Thomas Pickering and Adm. Mike Mullen, former chairman of the Joint Chiefs of Staff, to submit to new questioning about the scope of the Accountability Review Board they led in the fall. The request Monday was not a full congressional subpoena.

Obama noted that the e-mails on the talking points had been provided to Congress months ago. Republicans say the e-mail chain shows that the administration sought to avoid pinning the assault on al-Qaeda-linked militants because a successful terrorist attack could have damaged Obama’s reelection chances.

The administration did not squarely call the assault terrorism in public for several days, but Obama said that conclusion was presented so soon that it “defies logic” to accuse the White House of a conspiracy.

“The fact that this keeps on getting churned out, frankly, has a lot to do with political motivations,” Obama said. “They’ve used it for fundraising.”

Three Republican senators promptly accused Obama of dodging the issue and called for a joint congressional committee to investigate further. Sens. John McCain (R-Ariz.), Lindsey O. Graham (R-S.C.) and Kelly Ayotte (R-N.H.) said Obama referred only generically to terrorism the day after the attacks and wouldn’t go further.

“The administration is spinning the American people and stonewalling Congress,” the senators said in a joint statement.