WASHINGTON -- In the first 48 hours after the deadly Sept. 11 attacks on U.S. diplomatic outposts in Libya, senior Obama administration officials strongly alluded to a terrorist assault and repeatedly declined to link it to an anti-Muslim video that drew protests elsewhere in the region, transcripts of briefings show.

The administration’s initial accounts, however, changed dramatically in the following days, according to a review of briefing transcripts and administration statements, with a new narrative emerging Sept. 16 when U.S. ambassador to the United Nations Susan Rice asserted in a series of TV appearances that the best information available indicated that the attack had spun off from a protest over the video.

What prompted that pivot remains a mystery amid a closely contested presidential election and Republican allegations that President Barack Obama intentionally used outrage over the video to mask administration policy missteps that led to the deaths of four Americans, including U.S. Ambassador to Libya Christopher Stevens. The issue is sure to arise when Obama and his Republican rival Mitt Romney meet Monday to debate foreign policy.

Paul Pillar, a former top U.S. intelligence analyst on the Middle East, said that it’s natural with such incidents for accounts to change as new information is gathered. “You have not only a fog of war situation, but fragmentary, incomplete information, and as the responsible agencies develop and acquire better information, the explanations are naturally going to evolve,” he said.

But the administration’s statements offer an ironic twist on the “fog-of-war” phenomenon: They apparently were more accurate on the day after the attacks than they were when Rice made her TV appearances four days later. Administration officials so far have provided no detailed explanation for the change.

Tommy Vietor, a spokesman for the National Security Council, declined to comment for this report beyond saying that, "These issues have been covered in countless comments by the president and briefings."

State Department deputy spokesman Mark Toner declined to address specifics. "An independent board is conducting a thorough review of the assault on our post in Benghazi. Once we have the board’s comprehensive account of what happened, findings and recommendations, we can fully address these matters," he said in an email.

On the day after the attack, transcripts show, senior administration officials, briefing reporters, declined in response to three direct questions to link the Benghazi assaults to protests over the video. One senior official told reporters during the briefing that “unidentified Libyan extremists” launched what was “clearly a complex attack.” The official isn’t named because such briefings typically come on the condition of anonymity.

At campaign stops in Colorado and Nevada the next day, Sept. 13, Obama referred to the Benghazi assault as “an act of terror.” At the State Department press briefing that day, spokeswoman Victoria Nuland was asked directly and repeatedly whether there was a link between the video protests and the attack on the U.S. consulate.

While she mentioned that commentary on social media was making the link “to this reprehensible video,” Nuland emphasized several times that there wasn’t enough information for officials to make that leap, even though some news reports, including those of The New York Times and Agence France Presse, were citing unnamed witnesses in Libya who said that anger over the video was the reason the consulate was targeted.