Mitt Romney's campaign accused President Barack Obama's administration on Thursday of trying to "mislead the American people" over the attack that killed the US ambassador to Libya.
"We were initially told that this was a spontaneous demonstration in response to a video that was on YouTube," the top political adviser to the Republican White House hopeful, Eric Fehrnstrom, told Fox News.
"Now we're learning that it was a pre-planned terrorist attack, conducted on the anniversary of 9/11 and that it involved elements of Al Qaeda."
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Obama "needs to be held accountable for his administration's attempts to mislead the American people about what happened in Benghazi," the Republican aide added.
Republican opponents accuse the Obama administration of downplaying and changing its story about the attack in eastern Libya two weeks ago that claimed the lives of four Americans, in a bid to paper over possible security or intelligence lapses that may have contributed to the deaths.
Libyan officials say they believe the assault on the consulate, which included the firing of rocket-propelled grenades and several hours of small arms fire, was pre-planned in advance by foreign extremists.
Asked directly if he thought the Obama administration was lying, Fehrnstrom did not use the word but suggested it was possible.
"If in fact there were early intelligence reports indicating that this was a pre-planned terrorist attack, and instead the administration was trying to persuade the American people that it was a spontaneous demonstration in response to a YouTube video, then of course, there does appear to be an attempt to mislead," he said.
"This president would prefer not to talk about this attack on Benghazi being a terrorist attack. But I think we need to level with the American people about what's happening in that part of the world."
The White House had earlier Thursday accused Republicans of using the US deaths in Libya for political gain.
"There was an attempt by Republicans beginning with governor Romney to try to turn this event into a partisan issue," said White House spokesman Jay Carney, accusing Republicans of trying to "score political points out of a terror attack."
US ambassador to the United Nations Susan Rice initially said the attack was by extremists taking advantage of a spontaneous demonstration against an anti-Islamic film made by Christian extremists in the United States.
Carney said last week and on Wednesday that the attack was terrorism. On Tuesday, Romney accused the president of papering over the incident in which US ambassador Christopher Stevens was killed.
Obama has not yet used the word "terrorism" specifically in reference to the attack, but in his initial reaction he did say that "no acts of terror will ever shake the resolve" of Americans.
On Wednesday, Secretary of State Hillary Clinton appeared to suggest there could have been an Al-Qaeda link to the attack on the consulate.
A senior administration official later rowed back her remarks.
