After two weeks of changing stories from the Obama administration regarding the Libya terror attack, Republican lawmakers are putting increasing pressure on the president and his advisers to explain why they made such "implausible" statements in the days following the strike.

Members of Congress, frustrated over an apparently light-on-details intelligence briefing last week and the initial insistence by officials that the attack was linked to anger over an anti-Islam film, fired off a round of letters this week seeking clear answers. Mitt Romney, after initially laying low over the changing Libya narrative, also has started to hammer the president over the issue.

Republicans now are openly suggesting that the administration may have covered up details of the attack for political purposes.

"We are getting close to an election, and all I can think of is they're just trying to keep the facts unknown until after the election," Rep. Buck McKeon, R-Calif., chairman of the House Armed Services Committee, told Fox News on Wednesday. "The way they're handling this is so incompetent."

White House Press Secretary Jay Carney said Wednesday that President Obama considers the strike a "terrorist attack." Though Obama did not refer to it as such in his address Tuesday to the U.N. General Assembly, several administration officials, including Carney and Secretary of State Hillary Clinton, have used the term since last week.

The administration, though, still has not publicly rejected comments made two Sundays ago in several TV interviews by U.S. Ambassador to the United Nations Susan Rice. Rice claimed on "Fox News Sunday" and other programs that the attack was a spontaneous assault tied to the anti-U.S. protests in Cairo. Rice, like other administration officials, said the attack was not pre-planned.

Four senators wrote a letter to Rice on Tuesday asking about her "troubling statements that are inconsistent with the facts" and demanding an explanation.

"By the date of your comments, it was already clear that the attack in Libya was a terrorist attack, and that heavily armed and well trained attackers appeared to have prepared for an opportunity to attack U.S. interests," they wrote. "Yet, you repeatedly asserted the implausible explanation that the attack in Benghazi was a spontaneous reaction to the video despite growing evidence to the contrary. ... We look forward to a timely response that explains how the U.S. Ambassador to the United Nations could characterize an attack on a U.S. consulate so inaccurately five days after a terrorist attack that killed four Americans."

The letter was signed by Sens. John McCain, R-Ariz.; Kelly Ayotte, R-N.H.; Lindsey Graham, R-S.C.; and Ron Johnson, R-Wis.

Sens. Johnny Isakson, R-Ga., and Bob Corker, R-Tenn., wrote a separate letter Wednesday to Secretary of State Hillary Clinton asking about security measures in Benghazi prior to the consulate attack.

"Specifically, we are concerned over the apparent lack of security preparations made despite a demonstrable increase in risks to U.S. officials and facilities in Benghazi in the period leading up to the attacks," they wrote, citing attacks earlier this year on the consulate, the British ambassador's convoy and the International Committee of the Red Cross office.

House Republicans including McKeon meanwhile sent a letter to Obama asking about intelligence leading up to the attack and criticizing the administration's discussion of the strike in its aftermath.

"We are also disturbed by the public statements made by members of the administration that would lead the American public to believe this attack was a protest gone wrong, rather than what it truly was - a terrorist attack on the United States on the anniversary of 9/11," they wrote.

Slamming the response to the attack as a "pre-9/11 mindset," they asked the Obama administration what it plans to do to protect other U.S. interests abroad from being targeted.

Obama advisers, though, have denied any attempt to mislead the public.

Carney said Wednesday that the administration has provided as much information as possible, stressing that the investigation must be allowed to take its course.

Carney said the administration will provide more facts to the public as they emerge.

The Romney campaign, though, pressed Obama to personally condemn the attack as terrorism.

"This is now the second time the White House press secretary has said something that President Obama has declined to admit. If the president thinks the tragic events in Libya were acts of terrorism, he should say so himself," Romney spokesman Ryan Williams said, echoing Romney's comments in an interview with Fox News a day earlier.

Libyan President Mohamed Magarief, in an interview with NBC News on Wednesday, reiterated his claim that the anti-Islam film had nothing to do with the attack in Libya.