* ABC News report says emails were extensively edited
* Democrats say Republican charges politically motivated (Recasts with details, quotes)
The Obama administration denied Republican accusations of a cover-up in last year's deadly attack in Libya, moving on Friday to defuse a renewed political controversy after a news report said memos on the incident were edited to omit references to a CIA warning of an al Qaeda threat.
ABC News reported emails between the White House, State Department and intelligence agencies about the Benghazi attack went through 12 extensive revisions and were scrubbed clean of warnings about a militant threat.
The ABC report came as Republicans in Congress have stepped up efforts to criticize the Obama administration's response to the attack by suspected Islamist militants, with a growing focus on the role of then-Secretary of State Hillary Clinton, a potential Democratic presidential contender in 2016.
The so-called "talking point" memos were used to prepare U.S. Ambassador to the United Nations Susan Rice before she appeared on television talk shows to discuss the Sept. 11, 2012, attack on the U.S. mission in which Ambassador Christopher Stevens and three other Americans were killed.
In one email exchange, the State Department's top spokeswoman at the time, Victoria Nuland, objected to including the CIA's reference to intelligence about the threat from al Qaeda in Benghazi and eastern Libya.
That "could be abused by members (of Congress) to beat up the State Department for not paying attention to warnings, so why would we want to feed that either? Concerned," Nuland wrote in the email obtained by ABC News.
A source familiar with the Benghazi communications said Nuland was concerned the talking points went further than what she was allowed to say during her briefings and that "the CIA was attempting to exonerate itself at the State Department's expense."
But the source said the deletion of references to al Qaeda and the CIA's warnings came after a White House meeting on the day before Susan Rice appeared on the Sunday talk shows and Nuland was not at the meeting.
The mistrust between government agencies revealed in the documents offered an unusual peek into the administration's internal rivalries and displayed a rare crack in its usual discipline about messaging and public image.
'PURE, PROLONGED POLITICAL PROCESS'
Democrats have dismissed the Republican attacks as politically motivated and they had not gained much public momentum until this week. The ABC report could draw fresh attention to the allegations, however, and give them new life.
"It's a tragedy, but I hate to see it turned into a pure, prolonged, political process that really doesn't tell us anything new about the facts," Secretary of State John Kerry, who replaced Clinton, said in a Google+ Hangout chat.
A senior administration official said there was nothing in the new documents to contradict the administration's claim the talking points were based on intelligence community assessments.
"The White House made stylistic edits to the talking points to emphasize that the investigation was ongoing as to who was responsible, to simplify certain phrasing, and to clarify that the Benghazi mission was not a consulate," the official said.
At a high-profile congressional hearing two days ago and in public statements, Republicans have renewed months-old charges the email traffic shows the administration tried to play down the Benghazi assault because it came at the height of the U.S. presidential campaign and might have made President Barack Obama look weak on national security.
Republican House of Representatives Speaker John Boehner demanded on Thursday that the administration release emails on its handling of the attack. The emails reported by ABC had been shown to Congress, but lawmakers were not given copies, officials said.
The pro-Republican Super PAC American Crossroads released a web video on Friday focusing on questions about Clinton's role in a possible "cover-up" over the evolving explanations for the incident.
"Why did she blame a video? And was she part of a cover-up?" the video asks. "Americans deserve the truth."
The Republican National Committee sent out portions of the ABC report in an email headlined "Obama's Bungled Benghazi Response."
Congressman Elijah Cummings, a Maryland Democrat on the House of Representatives Oversight and Government Reform Committee, said the Republican accusations were an attempt to damage Clinton in case she decides to run for president in 2016.
"It is so much an effort ... to harm her before she even makes a decision and then to make sure they've got some material after she decides to run for president, assuming she does," he told MSNBC.